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This means it might contain formatting issues, incorrect code, conceptual problems, or other severe issues.
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{{task|Iteration}}
;Task: Loop over multiple arrays (or lists or tuples or whatever they're called in your language) and display the ''i'' th element of each.
Use your language's "for each" loop if it has one, otherwise iterate through the collection in order with some other loop.
For this example, loop over the arrays: (a,b,c) (A,B,C) (1,2,3) to produce the output: aA1 bB2 cC3
If possible, also describe what happens when the arrays are of different lengths.
;Related tasks:
- [[Loop over multiple arrays simultaneously]]
- [[Loops/Break]]
- [[Loops/Continue]]
- [[Loops/Do-while]]
- [[Loops/Downward for]]
- [[Loops/For]]
- [[Loops/For with a specified step]]
- [[Loops/Foreach]]
- [[Loops/Increment loop index within loop body]]
- [[Loops/Infinite]]
- [[Loops/N plus one half]]
- [[Loops/Nested]]
- [[Loops/While]]
- [[Loops/with multiple ranges]]
- [[Loops/Wrong ranges]]
360 Assembly
* Loop over multiple arrays simultaneously 09/03/2017
LOOPSIM CSECT
USING LOOPSIM,R12 base register
LR R12,R15
LA R6,1 i=1
LA R7,3 counter=3
LOOP LR R1,R6 i
SLA R1,1 *2
LH R2,R-2(R1) r(i)
XDECO R2,PG edit r(i)
LA R1,S-1(R6) @s(i)
MVC PG+3(1),0(R1) output s(i)
LA R1,Q-1(R6) @q(i)
MVC PG+7(1),0(R1) output q(i)
XPRNT PG,80 print s(i),q(i),r(i)
LA R6,1(R6) i++
BCT R7,LOOP decrement and loop
BR R14 exit
S DC C'a',C'b',C'c'
Q DC C'A',C'B',C'C'
R DC H'1',H'2',H'3'
PG DC CL80' ' buffer
YREGS
END LOOPSIM
{{out}}
a A 1
b B 2
c C 3
ACL2
(defun print-lists (xs ys zs) (if (or (endp xs) (endp ys) (endp zs)) nil (progn$ (cw (first xs)) (cw "~x0~x1~%" (first ys) (first zs)) (print-lists (rest xs) (rest ys) (rest zs))))) (print-lists '("a" "b" "c") '(A B C) '(1 2 3))
Ada
with Ada.Text_IO; use Ada.Text_IO;
procedure Array_Loop_Test is
type Array_Index is range 1..3;
A1 : array (Array_Index) of Character := "abc";
A2 : array (Array_Index) of Character := "ABC";
A3 : array (Array_Index) of Integer := (1, 2, 3);
begin
for Index in Array_Index'Range loop
Put_Line (A1 (Index) & A2 (Index) & Integer'Image (A3
(Index))(2));
end loop;
end Array_Loop_Test;
ALGOL 68
{{works with|ALGOL 68|Revision 1 - no extensions to language used}}
{{works with|ALGOL 68G|Any - tested with release [http://sourceforge.net/projects/algol68/files/algol68g/algol68g-1.18.0/algol68g-1.18.0-9h.tiny.el5.centos.fc11.i386.rpm/download
1.18.0-9h.tiny]}} {{wont work with|ELLA ALGOL 68|Any (with appropriate job cards) - tested with release [http://sourceforge.net/projects/algol68/files/algol68toc/algol68toc-1.8.8d/algol68toc-1.8-8d.fc9.i386.rpm/download
1.8-8d] - due to extensive use of '''format'''[ted] ''transput''}}
[]UNION(CHAR,INT) x=("a","b","c"), y=("A","B","C"),
z=(1,2,3);
FOR i TO UPB x DO
printf(($ggd$, x[i], y[i], z[i], $l$))
OD
{{out}}
aA1
bB2
cC3
ALGOL W
begin
% declare the three arrays %
string(1) array a, b ( 1 :: 3 );
integer array c ( 1 :: 3 );
% initialise the arrays - have to do this element by element in Algol W %
a(1) := "a"; a(2) := "b"; a(3) := "c";
b(1) := "A"; b(2) := "B"; b(3) := "C";
c(1) := 1; c(2) := 2; c(3) := 3;
% loop over the arrays %
for i := 1 until 3 do write( i_w := 1, s_w := 0, a(i), b(i), c(i) );
end.
If the arrays are not the same length, a subscript range error would occur when a non-existant element was accessed.
AppleScript
{{Trans|JavaScript}} (Functional ES 5 zipListsWith version)
If we have a generic Applescript '''map''' function, we can use it to write a generic '''zipListsWith''', which applies a given function over lists derived from the nth members of an arbitrary list of (equal-length) lists. (Where lists are of uneven length, items beyond the maximum shared length are ignored).
-- ZIP LISTS WITH FUNCTION --------------------------------------------------- -- zipListsWith :: ([a] -> b) -> [[a]] -> [[b]] on zipListsWith(f, xss) set n to length of xss script on |λ|(_, i) script on |λ|(xs) item i of xs end |λ| end script if i ≤ n then apply(f, (map(result, xss))) else {} end if end |λ| end script if n > 0 then map(result, item 1 of xss) else [] end if end zipListsWith -- TEST ( zip lists with concat ) ------------------------------------------- on run intercalate(linefeed, ¬ zipListsWith(concat, ¬ [["a", "b", "c"], ["A", "B", "C"], [1, 2, 3]])) end run -- GENERIC FUNCTIONS --------------------------------------------------------- -- apply (a -> b) -> a -> b on apply(f, a) mReturn(f)'s |λ|(a) end apply -- concat :: [[a]] -> [a] | [String] -> String on concat(xs) if length of xs > 0 and class of (item 1 of xs) is string then set acc to "" else set acc to {} end if repeat with i from 1 to length of xs set acc to acc & item i of xs end repeat acc end concat -- intercalate :: Text -> [Text] -> Text on intercalate(strText, lstText) set {dlm, my text item delimiters} to {my text item delimiters, strText} set strJoined to lstText as text set my text item delimiters to dlm return strJoined end intercalate -- map :: (a -> b) -> [a] -> [b] on map(f, xs) tell mReturn(f) set lng to length of xs set lst to {} repeat with i from 1 to lng set end of lst to |λ|(item i of xs, i, xs) end repeat return lst end tell end map -- Lift 2nd class handler function into 1st class script wrapper -- mReturn :: Handler -> Script on mReturn(f) if class of f is script then f else script property |λ| : f end script end if end mReturn
{{Out}}
aA1
bB2
cC3
But a transpose function might be simpler:
-- CONCAT MAPPED OVER A TRANSPOSITION ---------------------------------------- on run unlines(map(concat, transpose([["a", "b", "c"], ["A", "B", "C"], [1, 2, 3]]))) end run -- GENERIC FUNCTIONS --------------------------------------------------------- -- concat :: [[a]] -> [a] | [String] -> String on concat(xs) if length of xs > 0 and class of (item 1 of xs) is string then set acc to "" else set acc to {} end if repeat with i from 1 to length of xs set acc to acc & item i of xs end repeat acc end concat -- intercalate :: String -> [String] -> String on intercalate(s, xs) set {dlm, my text item delimiters} to {my text item delimiters, s} set str to xs as text set my text item delimiters to dlm return str end intercalate -- map :: (a -> b) -> [a] -> [b] on map(f, xs) tell mReturn(f) set lng to length of xs set lst to {} repeat with i from 1 to lng set end of lst to |λ|(item i of xs, i, xs) end repeat return lst end tell end map -- Lift 2nd class handler function into 1st class script wrapper -- mReturn :: Handler -> Script on mReturn(f) if class of f is script then f else script property |λ| : f end script end if end mReturn -- transpose :: [[a]] -> [[a]] on transpose(xss) script column on |λ|(_, iCol) script row on |λ|(xs) item iCol of xs end |λ| end script map(row, xss) end |λ| end script map(column, item 1 of xss) end transpose -- unlines :: [String] -> String on unlines(xs) intercalate(linefeed, xs) end unlines
{{Out}}
aA1
bB2
cC3
AutoHotkey
=== Pseudo-arrays === [http://www.autohotkey.com/docs/commands/StringSplit.htm StringSplit] creates a pseudo-array
List1 = a,b,c
List2 = A,B,C
List3 = 1,2,3
MsgBox, % LoopMultiArrays()
List1 = a,b,c,d,e
List2 = A,B,C,D
List3 = 1,2,3
MsgBox, % LoopMultiArrays()
;---------------------------------------------------------------------------
LoopMultiArrays()
{ ; print the ith element of each
;---------------------------------------------------------------------------
local Result
StringSplit, List1_, List1, `,
StringSplit, List2_, List2, `,
StringSplit, List3_, List3, `,
Loop, % List1_0
Result .= List1_%A_Index% List2_%A_Index% List3_%A_Index% "`n"
Return, Result
}
An array that is too short on creation will return empty strings when trying to retrieve further elements. The 2nd Message box shows:
aA1
bB2
cC3
dD
e
Real arrays
{{works with|AutoHotkey_L}} In [[AutoHotkey_L]], we can use true arrays ([http://l.autohotkey.com/docs/Objects.htm Objects]) and the [http://l.autohotkey.net/docs/commands/For.htm For loop].
List1 := ["a", "b", "c"]
List2 := ["A", "B", "C"]
List3 := [ 1 , 2 , 3 ]
MsgBox, % LoopMultiArrays()
List1 := ["a", "b", "c", "d", "e"]
List2 := ["A", "B", "C", "D"]
List3 := [1,2,3]
MsgBox, % LoopMultiArrays()
LoopMultiArrays() {
local Result
For key, value in List1
Result .= value . List2[key] . List3[key] "`n"
Return, Result
}
The output from this script is identical to the first one.
AWK
BEGIN {
split("a,b,c", a, ",");
split("A,B,C", b, ",");
split("1,2,3", c, ",");
for(i = 1; i <= length(a); i++) {
print a[i] b[i] c[i];
}
}
Axe
Note that in this example, we use a few bytes from each of L₁, L₂, and L₃ for simplicity. In practice, one would want to arrange the arrays to all fit within L₁ to avoid volatility issues with L₂ and L₃.
'a'→{L₁}
'b'→{L₁+1}
'c'→{L₁+2}
'A'→{L₂}
'B'→{L₂+1}
'C'→{L₂+2}
1→{L₃}
2→{L₃+1}
3→{L₃+2}
For(I,0,2)
Disp {L₁+I}►Char,{L₂+I}►Char,{L₃+I}►Dec,i
End
Babel
There are two ways to do this in Babel. First, you could transpose the lists:
main: { (('a' 'b' 'c')('A' 'B' 'C')('1' '2' '3'))
simul_array }
simul_array!:
{ trans
{ { << } each "\n" << } each }
The 'trans' operator substitutes nil in the portions of each transposed column wherever a row list was shorter than the longest row list. The '<<' operator prints nothing if the top-of-stack is nil.
A more literal solution to the problem as presented would be to iterate across each list using a user-defined cdrall operator:
main: { (('a' 'b' 'c')('A' 'B' 'C')('1' '2' '3'))
simul_array }
simul_array!:
{{ dup
{ car << } each
cdrall }
{ allnil? not }
while }
cdrall!: { { { cdr } each -1 take } nest }
-- only returns true if all elements of a list are nil
allnil?!:
{ 1 <->
{ car nil?
{ zap 0 last }
{ nil }
if} each }
This solution is formally identical to the first and will handle lists of varying lengths by printing inserting nil and printing nothing for the tail ends of the short lists.
BBC BASIC
DIM array1$(2), array2$(2), array3%(2)
array1$() = "a", "b", "c"
array2$() = "A", "B", "C"
array3%() = 1, 2, 3
FOR index% = 0 TO 2
PRINT array1$(index%) ; array2$(index%) ; array3%(index%)
NEXT
Befunge
There's no concept of an array data type in Befunge, but you'd typically store your arrays as sequences of data in the Befunge code space. You'd then loop over the range of indices required to access those arrays, and use the loop variable as an offset into each data area. For arrays of differing lengths, you'd need to manually check for an out-of-range index and deal with it appropriately.
:2g,:3g,:4gv
@_^#`2:+1,+55,<
abc
ABC
123
C
Given several arrays, especially if they are heterogeneous, the most ordinary way to loop over all of them is to simply use an index variable. Determining when to stop is generally done in some application-specific way.
#include <stdio.h> char a1[] = {'a','b','c'}; char a2[] = {'A','B','C'}; int a3[] = {1,2,3}; int main(void) { for (int i = 0; i < 3; i++) { printf("%c%c%i\n", a1[i], a2[i], a3[i]); } }
(Note: Some compilers may require a flag to accept this modern C code,
such as gcc -std=c99.)
On the other hand, it is possible to write a more generic higher-order iteration scheme, as demonstrated in [[Loop_over_multiple_arrays_simultaneously/C-Elaboration|this example]]. There, a type for arrays with runtime-specified lengths and polymorphic printing is defined, and the iteration continues up to the length of the shortest array.
C#
class Program { static void Main(string[] args) { char[] a = { 'a', 'b', 'c' }; char[] b = { 'A', 'B', 'C' }; int[] c = { 1, 2, 3 }; int min = Math.Min(a.Length, b.Length); min = Math.Min(min, c.Length); for (int i = 0; i < min; i++) Console.WriteLine("{0}{1}{2}", a[i], b[i], c[i]); } }
Using Enumerable.Zip (stops when either source runs out of elements):
int[] numbers = { 1, 2, 3, 4 }; string[] words = { "one", "two", "three" }; Console.WriteLine(numbers.Zip(words, (first, second) => first + " " + second));
Like how a perl programmer would write it (still using Zip):
Console.WriteLine((new[] { 1, 2, 3, 4 }).Zip(new[] { "a", "b", "c" }, (f, s) => f + " " + s));
Custom implementation for arrays of different lengths that pads with spaces after the end of the shorter arrays:
public static void Multiloop(char[] A, char[] B, int[] C) { var max = Math.Max(Math.Max(A.Length, B.Length), C.Length); for (int i = 0; i < max; i++) Console.WriteLine($"{(i < A.Length ? A[i] : ' ')}, {(i < B.Length ? B[i] : ' ')}, {(i < C.Length ? C[i] : ' ')}"); }
usage:
Multiloop(new char[] { 'a', 'b', 'c', 'd' }, new char[] { 'A', 'B', 'C' }, new int[] { 1, 2, 3, 4, 5 });
C++
With std::vectors:
#include <iostream> #include <vector> int main(int argc, char* argv[]) { std::vector<char> ls(3); ls[0] = 'a'; ls[1] = 'b'; ls[2] = 'c'; std::vector<char> us(3); us[0] = 'A'; us[1] = 'B'; us[2] = 'C'; std::vector<int> ns(3); ns[0] = 1; ns[1] = 2; ns[2] = 3; std::vector<char>::const_iterator lIt = ls.begin(); std::vector<char>::const_iterator uIt = us.begin(); std::vector<int>::const_iterator nIt = ns.begin(); for(; lIt != ls.end() && uIt != us.end() && nIt != ns.end(); ++lIt, ++uIt, ++nIt) { std::cout << *lIt << *uIt << *nIt << "\n"; } }
Using static arrays:
#include <iostream> int main(int argc, char* argv[]) { char ls[] = {'a', 'b', 'c'}; char us[] = {'A', 'B', 'C'}; int ns[] = {1, 2, 3}; for(size_t li = 0, ui = 0, ni = 0; li < sizeof(ls) && ui < sizeof(us) && ni < sizeof(ns) / sizeof(int); ++li, ++ui, ++ni) { std::cout << ls[li] << us[ui] << ns[ni] << "\n"; } }
C++11
With std::vectors:
#include <iostream> #include <vector> int main(int argc, char* argv[]) { auto lowers = std::vector<char>({'a', 'b', 'c'}); auto uppers = std::vector<char>({'A', 'B', 'C'}); auto nums = std::vector<int>({1, 2, 3}); auto ilow = lowers.cbegin(); auto iup = uppers.cbegin(); auto inum = nums.cbegin(); for(; ilow != lowers.end() and iup != uppers.end() and inum != nums.end() ; ++ilow, ++iup, ++inum) { std::cout << *ilow << *iup << *inum << "\n"; } }
Using static arrays:
#include <iostream> #include <iterator> int main(int argc, char* argv[]) { char lowers[] = {'a', 'b', 'c'}; char uppers[] = {'A', 'B', 'C'}; int nums[] = {1, 2, 3}; auto ilow = std::begin(lowers); auto iup = std::begin(uppers); auto inum = std::begin(nums); for(; ilow != std::end(lowers) and iup != std::end(uppers) and inum != std::end(nums) ; ++ilow, ++iup, ++inum ) { std::cout << *ilow << *iup << *inum << "\n"; } }
With std::arrays:
#include <iostream> #include <array> int main(int argc, char* argv[]) { auto lowers = std::array<char, 3>({'a', 'b', 'c'}); auto uppers = std::array<char, 3>({'A', 'B', 'C'}); auto nums = std::array<int, 3>({1, 2, 3}); auto ilow = lowers.cbegin(); auto iup = uppers.cbegin(); auto inum = nums.cbegin(); for(; ilow != lowers.end() and iup != uppers.end() and inum != nums.end() ; ++ilow, ++iup, ++inum ) { std::cout << *ilow << *iup << *inum << "\n"; } }
With std::arrays by indexes:
#include <iostream> #include <array> #include <algorithm> int main(int argc, char* argv[]) { auto lowers = std::array<char, 3>({'a', 'b', 'c'}); auto uppers = std::array<char, 3>({'A', 'B', 'C'}); auto nums = std::array<int, 3>({1, 2, 3}); auto const minsize = std::min( lowers.size(), std::min( uppers.size(), nums.size() ) ); for(size_t i = 0; i < minsize; ++i) { std::cout << lowers[i] << uppers[i] << nums[i] << "\n"; } }
Chapel
var a1 = [ "a", "b", "c" ];
var a2 = [ "A", "B", "C" ];
var a3 = [ 1, 2, 3 ];
for (x,y,z) in zip(a1, a2, a3) do
writeln(x,y,z);
Clojure
(doseq [s (map #(str %1 %2 %3) "abc" "ABC" "123")] (println s))
The sequence stops when the shortest list is exhausted.
COBOL
IDENTIFICATION DIVISION.
PROGRAM-ID. Loop-Over-Multiple-Tables.
DATA DIVISION.
WORKING-STORAGE SECTION.
01 A VALUE "abc".
03 A-Vals PIC X OCCURS 3 TIMES.
01 B VALUE "ABC".
03 B-Vals PIC X OCCURS 3 TIMES.
01 C VALUE "123".
03 C-Vals PIC 9 OCCURS 3 TIMES.
01 I PIC 9.
PROCEDURE DIVISION.
PERFORM VARYING I FROM 1 BY 1 UNTIL 3 < I
DISPLAY A-Vals (I) B-Vals (I) C-Vals (I)
END-PERFORM
GOBACK
.
Common Lisp
Using functional application
(mapc (lambda (&rest args) (format t "~{~A~}~%" args)) '(|a| |b| |c|) '(a b c) '(1 2 3))
If lists are different lengths, it stops after the shortest one.
Using LOOP
(loop for x in '("a" "b" "c") for y in '(a b c) for z in '(1 2 3) do (format t "~a~a~a~%" x y z))
D
import std.stdio, std.range; void main () { foreach (a, b, c; zip("abc", "ABC", [1, 2, 3])) writeln(a, b, c); }
{{out}}
aA1
bB2
cC3
zip() allows to specify the stopping policy. On default it stops when the shortest range is exhausted (same as StoppingPolicy.shortest):
import std.stdio, std.range; void main () { auto a1 = [1, 2]; auto a2 = [1, 2, 3]; alias StoppingPolicy sp; // Stops when the shortest range is exhausted foreach (p; zip(sp.shortest, a1, a2)) writeln(p.tupleof); writeln(); // Stops when the longest range is exhausted foreach (p; zip(sp.longest, a1, a2)) writeln(p.tupleof); writeln(); // Requires that all ranges are equal foreach (p; zip(sp.requireSameLength, a1, a2)) writeln(p.tupleof); }
{{out}}
11
22
11
22
03
11
22
Followed by an exception with message "Inequal-length ranges passed to Zip".
There is also std.range.lockstep:
import std.stdio, std.range; void main() { auto arr1 = [1, 2, 3, 4, 5]; auto arr2 = [6, 7, 8, 9, 10]; foreach (ref a, ref b; lockstep(arr1, arr2)) a += b; assert(arr1 == [7, 9, 11, 13, 15]); // Lockstep also supports iteration with an index variable foreach (index, a, b; lockstep(arr1, arr2)) writefln("Index %s: a = %s, b = %s", index, a, b); }
Lower level code that stops at the shortest length:
import std.stdio, std.algorithm; void main () { auto s1 = "abc"; auto s2 = "ABC"; auto a1 = [1, 2]; foreach (i; 0 .. min(s1.length, s2.length, a1.length)) writeln(s1[i], s2[i], a1[i]); }
{{out}}
aA1
bB2
Delphi
program LoopOverArrays;
{$APPTYPE CONSOLE}
uses SysUtils;
const
ARRAY1: array [1..3] of string = ('a', 'b', 'c');
ARRAY2: array [1..3] of string = ('A', 'B', 'C');
ARRAY3: array [1..3] of Integer = (1, 2, 3);
var
i: Integer;
begin
for i := 1 to 3 do
Writeln(Format('%s%s%d', [ARRAY1[i], ARRAY2[i], ARRAY3[i]]));
Readln;
end.
DWScript
If the arrays don't have the same bounds, an index out of bound exception will be triggered when attempting to access a non-existing element.
const a1 = ['a', 'b', 'c'];
const a2 = ['A', 'B', 'C'];
const a3 = [1, 2, 3];
var i : Integer;
for i := 0 to 2 do
PrintLn(Format('%s%s%d', [a1[i], a2[i], a3[i]]));
E
E lacks a nice way to do this; this is [http://wiki.erights.org/wiki/Parallel_iteration to be fixed, once we figure out what to do]. However, iteration over an List produces its indexes as keys, so a not entirely awful idiom exists:
def a1 := ["a","b","c"]
def a2 := ["A","B","C"]
def a3 := ["1","2","3"]
for i => v1 in a1 {
println(v1, a2[i], a3[i])
}
This will obviously fail if a2 or a3 are shorter than a1, and omit items if a2 or a3 are longer.
Given a parallel iteration utility, we might write this:
for [v1, v2, v3] in zip(a1, a2, a3) {
println(v1, v2, v3)
}
zip cannot yet be defined for all collections
(other than by iterating over each one and storing the results in a List
first); but we can define it for numeric-indexed collections such as
Lists, as below. Both a definition for any number of collections and two
collections is given; the latter in order to demonstrate the principle
without the clutter resulting from handling a variable number of
collections.
def zip {
to run(l1, l2) {
def zipped {
to iterate(f) {
for i in int >= 0 {
f(i, [l1.fetch(i, fn { return }),
l2.fetch(i, fn { return })])
}
}
}
return zipped
}
match [`run`, lists] {
def zipped {
to iterate(f) {
for i in int >= 0 {
var tuple := []
for l in lists {
tuple with= l.fetch(i, fn { return })
}
f(i, tuple)
}
}
}
zipped
}
}
(This will stop when the end of the shortest collection is reached.)
EchoLisp
;; looping over different sequences : infinite stream, string, list and vector
;; loop stops as soon a one sequence ends.
;; the (iota 6) = ( 0 1 2 3 4 5) sequence will stop first.
(for ((i (in-naturals 1000)) (j "ABCDEFGHIJK") (k (iota 6)) (m #(o p q r s t u v w)))
(writeln i j k m))
1000 "A" 0 o
1001 "B" 1 p
1002 "C" 2 q
1003 "D" 3 r
1004 "E" 4 s
1005 "F" 5 t
Efene
@public
run = fn () {
lists.foreach(fn ((A, B, C)) { io.format("~s~n", [[A, B, C]]) },
lists.zip3("abc", "ABC", "123"))
}
If the lists are not all the same length, an error is thrown.
Ela
open monad io list imperative
xs = zipWith3 (\x y z -> show x ++ show y ++ show z) ['a','b','c']
['A','B','C'] [1,2,3]
print x = do putStrLn x
print_and_calc xs = do
xss <- return xs
return $ each print xss
print_and_calc xs ::: IO
The code above can be written shorter. First there is no need in lists as soon as strings in Ela can be treated as lists. Also instead of explicit labmda one can use partial application and a standard composition operator:
xs = zipWith3 (\x -> (x++) >> (++)) "abc" "ABC"
"123"
Elixir
'''string list:'''
l1 = ["a", "b", "c"] l2 = ["A", "B", "C"] l3 = ["1", "2", "3"] IO.inspect List.zip([l1,l2,l3]) |> Enum.map(fn x-> Tuple.to_list(x) |> Enum.join end) #=> ["aA1", "bB2", "cC3"]
'''char_list:'''
l1 = 'abc' l2 = 'ABC' l3 = '123' IO.inspect List.zip([l1,l2,l3]) |> Enum.map(fn x-> Tuple.to_list(x) end) #=> ['aA1', 'bB2', 'cC3']
When the length of the list is different:
iex(1)> List.zip(['abc','ABCD','12345']) |> Enum.map(&Tuple.to_list(&1)) ['aA1', 'bB2', 'cC3'] iex(2)> List.zip(['abcde','ABC','12']) |> Enum.map(&Tuple.to_list(&1)) ['aA1', 'bB2']
The zipping finishes as soon as any enumerable completes.
Elena
ELENA 4.1 :
import system'routines;
import extensions;
public program()
{
var a1 := new string[]::("a","b","c");
var a2 := new string[]::("A","B","C");
var a3 := new int[]::(1,2,3);
for(int i := 0, i < a1.Length, i += 1)
{
console.printLine(a1[i], a2[i], a3[i])
};
programUsingZip();
console.readChar()
}
Using zipBy extension:
import system'routines.
import extensions.
public program
{
var a1 := new string[]::("a","b","c");
var a2 := new string[]::("A","B","C");
var a3 := new int[]::(1,2,3);
var zipped := a1.zipBy(a2,(first,second => first + second.toString() ))
.zipBy(a3, (first,second => first + second.toString() ));
zipped.forEach:(e)
{ console.writeLine:e };
console.readChar();
}
{{out}}
aA1
bB2
cC3
Erlang
Shortest option:
lists:zipwith3(fun(A,B,C)-> io:format("~s~n",[[A,B,C]]) end, "abc", "ABC", "123").
However, as every expression in Erlang has to return something, printing text returns 'ok'. A list with as many 'ok's as there are lines printed will thus be created. The technically cleanest way to do things would be with lists:foreach/2, which also guarantees evaluation order:
lists:foreach(fun({A,B,C}) -> io:format("~s~n",[[A,B,C]]) end, lists:zip3("abc", "ABC", "123")).
If the lists are not all the same length, an error is thrown.
Euphoria
There are many ways to do this. All of them rely on what strings really are. If they are all "strings", it's quite easy:
sequence a, b, c
a = "abc"
b = "ABC"
c = "123"
for i = 1 to length(a) do
puts(1, a[i] & b[i] & c[i] & "\n")
end for
If not, and the other sequence is known to contain only integers:
sequence a, b, c
a = "abc"
b = "ABC"
c = {1, 2, 3}
for i = 1 to length(a) do
printf(1, "%s%s%g\n", {a[i], b[i], c[i]})
end for
A general solution for any arbitrary strings of characters or numbers can get a bit complex. This is because of how sequences are stored and printed out. One possible answer is as follows, if you know that only alphanumeric characters are used:
for i = 1 to length(a) do
if (a[i] >= '0' and a[i] <= '9') then
a[i] -= '0'
end if
if (b[i] >= '0' and b[i] <= '9') then
b[i] -= '0'
end if
if (c[i] >= '0' and c[i] <= '9') then
c[i] -= '0'
end if
printf(1, "%s%s%s\n", {a[i], b[i], c[i]})
end for
Just as in Java, using single quotes around a character gives you its "char value". In Euphoria, though, it is simply that character's code in ASCII.
With all three of the above solutions, if any of the strings are smaller than the first, it will return an error.
=={{header|F_Sharp|F#}}==
for c1,c2,n in Seq.zip3 ['a';'b';'c'] ['A';'B';'C'] [1;2;3] do printfn "%c%c%d" c1 c2 n
When one sequence is exhausted, any remaining elements in the other sequences are ignored.
Factor
"abc" "ABC" "123" [ [ write1 ] tri@ nl ]
3each
Fantom
This will stop when it reaches the end of the shortest list.
class LoopMultiple
{
public static Void main ()
{
List arr1 := ["a", "b", "c"]
List arr2 := ["A", "B", "C"]
List arr3 := [1, 2, 3]
[arr1.size, arr2.size, arr3.size].min.times |Int i|
{
echo ("${arr1[i]}${arr2[i]}${arr3[i]}")
}
}
}
Forth
create a char a , char b , char c ,
create b char A , char B , char C ,
create c char 1 , char 2 , char 3 ,
: main
3 0 do cr
a i cells + @ emit
b i cells + @ emit
c i cells + @ emit
loop
cr
a b c
3 0 do cr
3 0 do
rot dup @ emit cell+
loop
loop
drop drop drop
;
Fortran
program main
implicit none
integer,parameter :: n_vals = 3
character(len=*),dimension(n_vals),parameter :: ls = ['a','b','c']
character(len=*),dimension(n_vals),parameter :: us = ['A','B','C']
integer,dimension(n_vals),parameter :: ns = [1,2,3]
integer :: i !counter
do i=1,n_vals
write(*,'(A1,A1,I1)') ls(i),us(i),ns(i)
end do
end program main
If the arrays are of different length (say, array ns has no third element), then when its turn comes the next unit of storage along from the second element will be accessed, its content interpreted as an integer, and its decimal value printed... If however, array bound checking is activated (or there is a memory access protection scheme that would detect this), a feature unavailable via many compilers and not the default on the rest, then an error will be detected and the run will be terminated, possibly with a somewhat helpful message.
If instead of reading the action had been to store a value into the array, then in the absence of bound checking, arbitrary damage will be done (to code or data) that will possibly result in something going wrong. And if you're lucky, it will happen swiftly.
FreeBASIC
' FB 1.05.0 Win64
Function min(x As Integer, y As Integer) As Integer
Return IIf(x < y, x, y)
End Function
Dim arr1(1 To 3) As String = {"a", "b", "c"}
Dim arr2(1 To 3) As String = {"A", "B", "C"}
Dim arr3(1 To 3) As Integer = {1, 2, 3}
For i As Integer = 1 To 3
Print arr1(i) & arr2(i) & arr3(i)
Next
Print
' For arrays of different lengths we would need to iterate up to the mimimm length of all 3 in order
' to get a contribution from each one. For example:
Dim arr4(1 To 4) As String = {"A", "B", "C", "D"}
Dim arr5(1 To 2) As Integer = {1, 2}
Dim ub As Integer = min(UBound(arr1), min(UBound(arr4), UBound(arr5)))
For i As Integer = 1 To ub
Print arr1(i) & arr2(i) & arr3(i)
Next
Print
Sleep
{{out}}
aA1
bB2
cC3
aA1
bB2
FunL
import lists.zip3
for x <- zip3( ['a', 'b', 'c'], ['A', 'B', 'C'], [1, 2, 3] )
println( x.mkString() )
{{out}}
aA1
bB2
cC3
Gambas
'''[https://gambas-playground.proko.eu/?gist=3a69e733694aeab3b72c6a5c0316535b Click this link to run this code]'''
Public Sub Main()
Dim a1 As String[] = ["a", "b", "c"]
Dim a2 As String[] = ["A", "B", "C"]
Dim a3 As String[] = ["1", "2", "3"]
Dim siC As Short
For siC = 0 To a1.Max
Print a1[siC] & a2[siC] & a3[siC]
Next
End
Output:
aA1
bB2
cC3
GAP
# The Loop function will apply some function to every tuple built by
taking
# the i-th element of each list. If one of them is exhausted before the
others,
# the loop continues at its begining. Only the longests lists will be
precessed only once.
Loop := function(a, f)
local i, j, m, n, v;
n := Length(a);
v := List(a, Length);
m := Maximum(v);
for j in [1 .. m] do
f(List([1 .. n], i -> a[i][1 + RemInt(j - 1, v[i])]));
od;
end;
# Here we simply print each "row"
f := function(u)
Perform(u, Print);
Print("\n");
end;
Loop([["a", "b", "c"], ["A", "B", "C"], [1, 2, 3]], f);
aA1
bB2
cC3
Loop([["a", "b"], ["A", "B", "C", "D", "E"], [1, 2, 3]], f);
aA1
bB2
aC3
bD1
aE2
Go
Go's "range clause" of a for statement only looks at a single iterable value (array, slice, etc). To access the three in parallel, they have to be explicitly indexed.
If a2 or a3 were
shorter, the program would panic with "runtime error: index out of
range".
If a2 or a3 were
longer, extra elements would be ignored.
Go's philosophy is that you should explicitly check for whatever
conditions are meaningful in your application and explicitly handle
whatever errors are plausible.
package main import "fmt" var a1 = []string{"a", "b", "c"} var a2 = []byte{'A', 'B', 'C'} var a3 = []int{1, 2, 3} func main() { for i := range a1 { fmt.Printf("%v%c%v\n", a1[i], a2[i], a3[i]) } }
Golfscript
["a" "b" "c"]:a;
["A" "B" "C"]:b;
["1" "2" "3"]:c;
[a b c]zip{puts}/
If there are arrays of different size, the shorter are treated as "null-padded" array.
Groovy
Solution:
def synchedConcat = { a1, a2, a3 -> assert a1 && a2 && a3 assert a1.size() == a2.size() assert a2.size() == a3.size() [a1, a2, a3].transpose().collect { "${it[0]}${it[1]}${it[2]}" } }
Test:
def x = ['a', 'b', 'c'] def y = ['A', 'B', 'C'] def z = [1, 2, 3] synchedConcat(x, y, z).each { println it }
{{out}}
aA1
bB2
cC3
Harbour
'''Using FOR EACH ... NEXT statement'''
PROCEDURE Main()
LOCAL a1 := { "a", "b", "c" }, ;
a2 := { "A", "B", "C", "D" }, ; // the last element "D" of this array will be ignored
a3 := { 1, 2, 3 }
LOCAL e1, e2, e3
FOR EACH e1, e2, e3 IN a1, a2, a3
Qout( e1 + e2 + hb_ntos( e3 ) )
NEXT
RETURN
Output: aA1 bB2 cC3 If the arrays are not of equal length, the iteration stops after the last item of the smaller array has been processed; any extra items of lengthier arrays are ignored (or in other words, the iteration counter never exceeds the length of the smaller array, thus preventing an 'out of subscript range' error).
Haskell
'''Using list comprehension'''
{-# LANGUAGE ParallelListComp #-} main = sequence [ putStrLn [x, y, z] | x <- "abd" | y <- "ABC" | z <- "123"]
'''Using Transpose'''
In this special case of transposing strings.
import Data.List main = mapM putStrLn $ transpose ["abd", "ABC", "123"]
'''Using ZipWith*'''
import Data.List main = mapM putStrLn $ zipWith3 (\a b c -> [a,b,c]) "abc" "ABC" "123"
'''Using applicative ZipLists'''
ZipLists generalize zipWith to any number of parameters
import Control.Applicative main = sequence $ getZipList $ (\x y z -> putStrLn [x, y, z]) <$> ZipList "abd" <*> ZipList "ABC" <*> ZipList "123"
Haxe
using Lambda;
using Std;
class Main
{
static function main()
{
var a = ['a', 'b', 'c'];
var b = ['A', 'B', 'C'];
var c = [1, 2, 3];
//Find smallest array
var len = [a, b, c]
.map(function(a) return a.length)
.fold(Math.min, 0x0FFFFFFF)
.int();
for (i in 0...len)
Sys.println(a[i] + b[i] + c[i].string());
}
}
HicEst
CHARACTER :: A = "abc"
REAL :: C(3)
C = $ ! 1, 2, 3
DO i = 1, 3
WRITE() A(i), "ABC"(i), C(i)
ENDDO
=={{header|Icon}} and {{header|Unicon}}==
The first solution uses co-expressions to produce parallel evaluation.
procedure main()
a := create !["a","b","c"]
b := create !["A","B","C"]
c := create !["1","2","3"]
while write(@a,@b,@c)
end
The second solution is more like other procedural languages and also handles unequal list lengths.
link numbers # for max
procedure main()
a := ["a","b","c"]
b := ["A","B","C","D"]
c := [1,2,3]
every i := 1 to max(*a,*b,*c) do
write(a[i]|"","\t",b[i]|"","\t",c[i]|"")
end
{{libheader|Icon Programming Library}} [http://www.cs.arizona.edu/icon/library/procs/numbers.htm Uses max from numbers]
J
For arrays of different types:
,.&:(":"0@>)/ 'abc' ; 'ABC' ; 1 2 3
aA1
bB2
cC3
This approach works by representing the digits as characters.
Where arrays are all the same type (all numeric or all string):
,.&:>/ 'abc' ; 'ABC' ; '123'
aA1
bB2
cC3
Both of these implementations reject arrays with conflicting lengths.
Other options include:
|: 'abc', 'ABC' ,:;":&> 1 2 3
aA1
bB2
cC3
|: 'abc', 'ABC',: '123'
aA1
bB2
cC3
These implementations pad short arrays with spaces.
Or:
|:>]&.>L:_1 'abc';'ABC';<1 2 3
┌─┬─┬─┐
│a│A│1│
├─┼─┼─┤
│b│B│2│
├─┼─┼─┤
│c│C│3│
└─┴─┴─┘
This implementation puts each item from each of the original lists into a box and forms an array of boxes. (A "box" is a immutable pointer to immutable data -- in other words value semantics instead of reference semantics -- and "putting an item into a box" is obtaining one of these pointers for that item.) This implementation extends any short array by providing empty boxes to represent the missing elements. (An "empty box" is what a programmer in another language might call "a pointer to a zero length array".)
Java
{{trans|JavaScript}}
String[] a = {"a","b","c"}; String[] b = {"A","B","C"}; int[] c = {1,2,3}; for(int i = 0;i < a.length;i++){ System.out.println(a[i] + b[i] + c[i]); }
If the first array is too short, it will stop
when it gets to the end of the first array.
If one of the other arrays is too short,
an ArrayIndexOutOfBoundException will be
thrown.
JavaScript
Imperative
This loops over the indices of the first array, and uses that to index into the others.
var a = ["a","b","c"], b = ["A","B","C"], c = [1,2,3], output = "", i; for (i = 0; i < a.length; i += 1) { output += a[i] + b[i] + c[i] + "\n"; }
If the b or c arrays are too "short", you will see the string "undefined" appear in the output.
Alternatively, we can nest a couple of calls to '''.forEach()''': one for the array of three arrays, and one for each of the three index positions:
var lstOut = ['', '', '']; [["a", "b", "c"], ["A", "B", "C"], ["1", "2", "3"]].forEach( function (a) { [0, 1, 2].forEach( function (i) { // side-effect on an array outside the function lstOut[i] += a[i]; } ); } ); // lstOut --> ["aA1", "bB2", "cC3"]
Functional composition
=ES5=
Functional options include folding across an array of arrays with the built-in '''Array.reduce()''', using a zipWith() function of suitable arity, or mapping over the output of a generic (any arity) zip() function.
(The generic zip function is the most tolerant – it simply ignores further elements in any arrays which are longer than the shortest array).
Reduce / fold:
(function (lstArrays) { return lstArrays.reduce( function (a, e) { return [ a[0] + e[0], a[1] + e[1], a[2] + e[2] ]; }, ['', '', ''] // initial copy of the accumulator ).join('\n'); })([ ["a", "b", "c"], ["A", "B", "C"], ["1", "2", "3"] ]);
A fixed arity ZipWith:
(function (x, y, z) { // function of arity 3 mapped over nth items of each of 3 lists // (a -> b -> c -> d) -> [a] -> [b] -> [c] -> [d] function zipWith3(f, xs, ys, zs) { return zs.length ? [f(xs[0], ys[0], zs[0])].concat( zipWith3(f, xs.slice(1), ys.slice(1), zs.slice(1))) : []; } function concat(x, y, z) { return ''.concat(x, y, z); } return zipWith3(concat, x, y, z).join('\n') })(["a", "b", "c"], ["A", "B", "C"], [1, 2, 3]);
Or we could write a generic '''zipListsWith''' applying some supplied function overs lists derived from the nth members of an arbitrary list of (equal-length) lists.
(function () { 'use strict'; // zipListsWith :: ([a] -> b) -> [[a]] -> [[b]] function zipListsWith(f, xss) { return (xss.length ? xss[0] : []) .map(function (_, i) { return f(xss.map(function (xs) { return xs[i]; })); }); } // concat :: [a] -> s function concat(lst) { return ''.concat.apply('', lst); } // TEST return zipListsWith( concat, [["a", "b", "c"], ["A", "B", "C"], [1, 2, 3]] ) .join('\n'); })();
{{Out}}
aA1
bB2
cC3
=ES6=
By transposition:
(() => { 'use strict'; // GENERIC FUNCTIONS ----------------------------------------------------- // concat :: [[a]] -> [a] const concat = xs => xs.length > 0 ? (() => { const unit = typeof xs[0] === 'string' ? '' : []; return unit.concat.apply(unit, xs); })() : []; // map :: (a -> b) -> [a] -> [b] const map = (f, xs) => xs.map(f); // transpose :: [[a]] -> [[a]] const transpose = xs => xs[0].map((_, col) => xs.map(row => row[col])); // unlines :: [String] -> String const unlines = xs => xs.join('\n'); // TEST ------------------------------------------------------------------ const xs = [ ['a', 'b', 'c'], ['A', 'B', 'C'], [1, 2, 3] ]; return unlines( map(concat, transpose(xs)) ); })();
{{Out}}
aA1
bB2
cC3
jq
The following solution is based on the assumption that all the arrays can be presented as an array of arrays. This allows any number of arrays to be handled.
Specifically, zip/0 expects an array of 0 or more arrays as its input. The first array determines the number of items in the output; nulls are used for padding.
# zip/0 emits [] if input is [].
def zip:
. as $in
| [range(0; $in[0]|length) as $i | $in | map( .[$i] ) ];
Example 1: [["a","b","c"], ["A","B","C"], [1,2,3]] | zip {{Out}}
[["a","A",1],["b","B",2],["c","C",3]]
To obtain the compact output used in the the task description, we can filter the results through a "pretty-print" function: def pp: reduce .[] as $i (""; . + "($i)");
Example 2: [["a","b","c"], ["A","B","C"], [1,2,3]] | zip | map(pp) {{Out}}
[
"aA1",
"bB2",
"cC3"
]
As already mentioned, the above definition of zip/0 privileges the first array, and if the subsequent arrays are of different lengths, null is used as a filler. Thus: [["a","b","c"], ["A","B"], [1]] | zip
produces: [["a","A",1],["b","B",null],["c",null,null]]
'''Handling jagged input''' An alternative approach would be use a variant of zip/0 that pads all arrays shorter than the longest with nulls. Here is such a variant:
# transpose a possibly jagged matrix
def transpose:
if . == [] then []
else (.[1:] | transpose) as $t
| .[0] as $row
| reduce range(0; [($t|length), (.[0]|length)] | max) as $i
([]; . + [ [ $row[$i] ] + $t[$i] ])
end;
Jsish
/* Loop over multiple arrays, in Jsish */ var a1 = ['a', 'b', 'c']; var a2 = ['A', 'B', 'C']; var a3 = [1, 2, 3]; puts('Equal sizes'); var arr = [a1, a2, a3]; var m = arr[0].length; for (var a of arr) if (a.length > m) m = a.length; for (var i = 0; i < m; i++) printf("%q%q%q\n", a1[i], a2[i], a3[i]); puts('\nUnequal sizes'); var a4 = []; var a5 = [4,5,6,7]; arr = [a1, a2, a3, a4, a5]; m = arr[0].length; for (a of arr) if (a.length > m) m = a.length; for (i = 0; i < m; i++) printf("%q%q%q%q%q\n", a1[i], a2[i], a3[i], a4[i], a5[i]); /* =!EXPECTSTART!= Equal sizes aA1 bB2 cC3 Unequal sizes aA1undefined4 bB2undefined5 cC3undefined6 /home/btiffin/forge/jsi/jsi-test/rosetta/loopOverMultipleArrays.jsi:19: warn: call with undefined var for argument arg 2 '...', in call to 'printf' <undefined>. (at or near "%q%q%q%q%q ") undefinedundefinedundefinedundefined7 =!EXPECTEND!= */
{{out}}
prompt$ jsish -u loopOverMultipleArrays.jsi
[PASS] loopOverMultipleArrays.jsi
Julia
'''With a higher order function''':
foreach(println, ('a', 'b', 'c'), ('A', 'B', 'C'), (1, 2, 3))
'''With a loop''':
for (i, j, k) in zip(('a', 'b', 'c'), ('A', 'B', 'C'), (1, 2, 3)) println(i, j, k) end
{{out}}
aA1
bB2
cC3
K
{,/$x}'+("abc";"ABC";1 2 3)
{{out}}
("aA1"
"bB2"
"cC3")
If the length of the arrays are different, then K croaks with "length error".
The following is a more general approach where
&/#:'x
calculates the minimum length of the arrays and is used to index the first elements in each array.
{+x[;!(&/#:'x)]}("abc";"ABC";"1234")
{{out}}
("aA1"
"bB2"
"cC3")
If the arrays are of different type, then the arrays must be converted to strings.
{a:,/'($:'x);+a[;!(&/#:'a)]}("abc";"ABC";1 2 3 4)
Kotlin
// version 1.0.6 fun main(args: Array<String>) { val a1 = charArrayOf('a', 'b', 'c') val a2 = charArrayOf('A', 'B', 'C') val a3 = intArrayOf(1, 2, 3) for(i in 0 .. 2) println("${a1[i]}${a2[i]}${a3[i]}") println() // For arrays of different sizes we would need to iterate up to the mimimm size of all 3 in order // to get a contribution from each one. val a4 = intArrayOf(4, 5, 6, 7) val a5 = charArrayOf('d', 'e') val minSize = Math.min(a2.size, Math.min(a4.size, a5.size)) // minimum size of a2, a4 and a5 for(i in 0 until minSize) println("${a2[i]}${a4[i]}${a5[i]}") }
{{out}}
aA1
bB2
cC3
A4d
B5e
LFE
(lists:zipwith3 (lambda (i j k) (io:format "~s~s~p~n" `(,i ,j ,k))) '(a b c) '(A B C) '(1 2 3))
If any of the data lists differ in size from the other,
the results will print out up to the shortest data list,
and then raise a function_clause error.
Erlang, and thus LFE, have zipwith and
zipwith3 for working with 2 and 3 simultaneous
sets of data respectively.
If you need more than that, you'll need to create your own "zip"
function with something like (: lists map
...).
Liberty BASIC
a$(1)="a" : a$(2)="b" : a$(3)="c"
b$(1)="A" : b$(2)="B" : b$(3)="C"
c(1)=1 : c(2)=2 : c(3)=3
for i = 1 to 3
print a$(i);b$(i);c(i)
next
Lisaac
Section Header
+ name := ARRAY_LOOP_TEST;
Section Public
- main <- (
+ a1, a2 : ARRAY[CHARACTER];
+ a3 : ARRAY[INTEGER];
a1 := ARRAY[CHARACTER].create 1 to 3;
a2 := ARRAY[CHARACTER].create 1 to 3;
a3 := ARRAY[INTEGER].create 1 to 3;
1.to 3 do { i : INTEGER;
a1.put ((i - 1 + 'a'.code).to_character) to i;
a2.put ((i - 1 + 'A'.code).to_character) to i;
a3.put i to i;
};
1.to 3 do { i : INTEGER;
a1.item(i).print;
a2.item(i).print;
a3.item(i).print;
'\n'.print;
};
);
LiveCode
Arrays
command loopArrays
local lowA, uppA, nums, z
put "a,b,c" into lowA
put "A,B,C" into uppA
put "1,2,3" into nums
split lowA by comma
split uppA by comma
split nums by comma
repeat with n = 1 to the number of elements of lowA
put lowA[n] & uppA[n] & nums[n] & return after z
end repeat
put z
end loopArrays
"list" processing
command loopDelimitedList
local lowA, uppA, nums, z
put "a,b,c" into lowA
put "A,B,C" into uppA
put "1,2,3" into nums
repeat with n = 1 to the number of items of lowA
put item n of lowA & item n of uppA & item n of nums
& return after z
end repeat
put z
end loopDelimitedList
Output - both behave similarly for this exercise.
aA1
bB2
cC3
When there are fewer elements than the first (or whatever the loop is based on), livecode will add an "empty" value. If we add a "d" to lowA and a 4 to nums we get the following:
aA1
bB2
cC3
d4
Logo
{{works with|UCB Logo}}
show (map [(word ?1 ?2 ?3)] [a b c] [A B C] [1 2 3])
; [aA1 bB2 cC3]
(foreach [a b c] [A B C] [1 2 3] [print (word ?1 ?2 ?3)]) ; as above,
one per line
Lua
This can be done with a simple for loop:
a1, a2, a3 = {'a' , 'b' , 'c' } , { 'A' , 'B' , 'C' } , { 1 , 2 , 3 } for i = 1, 3 do print(a1[i]..a2[i]..a3[i]) end
but it may be more enlightening (and in line with the spirit of the challenge) to use the generic for:
function iter(a, b, c) local i = 0 return function() i = i + 1 return a[i], b[i], c[i] end end for u, v, w in iter(a1, a2, a3) do print(u..v..w) end
Mathematica
This can be done with a built-in function:
MapThread[Print, {{"a", "b", "c"}, {"A", "B", "C"}, {1, 2, 3}}];
All arguments must be lists of the same length.
Mercury
:- import_module io. :- pred main(io::di, io::uo) is det.
:- implementation. :- import_module char, list, string.
main(!IO) :- A = ['a', 'b', 'c'], B = ['A', 'B', 'C'], C = [1, 2, 3], list.foldl_corresponding3(print_elems, A, B, C, !IO).
:- pred print_elems(char::in, char::in, int::in, io::di, io::uo) is det.
print_elems(A, B, C, !IO) :- io.format("%c%c%i\n", [c(A), c(B), i(C)], !IO).
The foldl_corresponding family of procedures all throw a
software_error/1
exception if the lengths of the lists are not the same.
=={{header|Modula-3}}==
```modula3
MODULE MultiArray EXPORTS Main;
IMPORT IO, Fmt;
TYPE ArrIdx = [1..3];
VAR
arr1 := ARRAY ArrIdx OF CHAR {'a', 'b', 'c'};
arr2 := ARRAY ArrIdx OF CHAR {'A', 'B', 'C'};
arr3 := ARRAY ArrIdx OF INTEGER {1, 2, 3};
BEGIN
FOR i := FIRST(ArrIdx) TO LAST(ArrIdx) DO
IO.Put(Fmt.Char(arr1[i]) & Fmt.Char(arr2[i]) &
Fmt.Int(arr3[i]) & "\n");
END;
END MultiArray.
MUMPS
Pieces of String version
LOOPMULT
N A,B,C,D,%
S A="a,b,c,d"
S B="A,B,C,D"
S C="1,2,3"
S D=","
F %=1:1:$L(A,",") W !,$P(A,D,%),$P(B,D,%),$P(C,D,%)
K A,B,C,D,%
Q
When there aren't enough elements, a null string will be returned from the $Piece function.
{{out}}
USER>d LOOPMULT^ROSETTA
aA1
bB2
cC3
dD
Local arrays version
LOOPMULU
N A,B,C,D,%
S A(1)="a",A(2)="b",A(3)="c",A(4)="d"
S B(1)="A",B(2)="B",B(3)="C",B(4)="D"
S C(1)="1",C(2)="2",C(3)="3"
; will error S %=$O(A("")) F Q:%="" W !,A(%),B(%),C(%) S
%=$O(A(%))
S %=$O(A("")) F Q:%="" W !,$G(A(%)),$G(B(%)),$G(C(%)) S %=$O(A(%))
K A,B,C,D,%
The commented out line will throw an
USER>D LOOPMULU^ROSETTA
aA1
bB2
cC3
dD
USER>D LOOPMULV^ROSETTA
aA1
bB2
cC3
dD
S %=$O(A("")) F Q:%="" W !,A(%),B(%),C(%) S %=$O(A(%))
^
<UNDEFINED>LOOPMULV+5^ROSETTA *C(4)
Nemerle
It "feels" better to use zip() for this, unfortunately the built in zip() only takes two lists.
using System;
using System.Console;
module LoopMultiple
{
Zip3[T1, T2, T3] (x : list[T1], y : list[T2], z : list[T3]) :
list[T1 * T2 * T3]
{
|(x::xs, y::ys, z::zs) => (x, y, z)::Zip3(xs, ys, zs)
|([], [], []) => []
|(_, _, []) => throw ArgumentNullException()
|(_, [], _) => throw ArgumentNullException()
|([], _, _) => throw ArgumentNullException()
}
Main() : void
{
def first = ['a', 'b', 'c'];
def second = ["A", "B", "C"];
def third = [1, 2, 3];
foreach ((x, y, z) in Zip3(first, second, third))
WriteLine($"$x$y$z");
}
}
Alternately: {{trans|C#}}
using System.Console;
module LoopMult
{
Main() : void
{
def first = array['a', 'b', 'c'];
def second = array['A', 'B', 'C'];
def third = array[1, 2, 3];
when (first.Length == second.Length && second.Length ==
third.Length)
foreach (i in [0 .. (first.Length - 1)])
WriteLine("{0}{1}{2}", first[i], second[i], third[i]);
}
}
NetRexx
/* NetRexx */
options replace format comments java crossref savelog symbols nobinary
say 'Using arrays'
aa = ['a', 'b', 'c', 'd']
bb = ['A', 'B', 'C']
cc = [1, 2, 3, 4]
loop x_ = 0 for aa.length
do
ax = aa[x_]
catch ArrayIndexOutOfBoundsException
ax = ' '
end
do
bx = bb[x_]
catch ArrayIndexOutOfBoundsException
bx = ' '
end
do
cx = cc[x_]
catch ArrayIndexOutOfBoundsException
cx = ' '
end
say ax || bx || cx
end x_
say 'Using indexed strings (associative arrays)'
ai = sampleData('a b c d')
bi = sampleData('A B C')
ci = sampleData('1 2 3 4')
loop x_ = 1 to ai[0]
say ai[x_] || bi[x_] || ci[x_]
end x_
method sampleData(arg) public static returns Rexx
smp = ' '
smp[0] = arg.words
loop i_ = 1 to smp[0]
smp[i_] = arg.word(i_)
end i_
return smp
{{out}}
Using arrays
aA1
bB2
cC3
d 4
Using indexed strings (associative arrays)
aA1
bB2
cC3
d 4
```
## NewLISP
```NewLISP
(map println '(a b c) '(A B C) '(1 2
3))
```
## Nim
```nim
let
a = @['a','b','c']
b = @["A","B","C"]
c = @[1,2,3]
for i in 0..2:
echo a[i], b[i], c[i]
```
=={{header|Oberon-2}}==
Works with oo2c version 2
```oberon2
MODULE LoopMArrays;
IMPORT
Out;
VAR
x,y: ARRAY 3 OF CHAR;
z: ARRAY 3 OF INTEGER;
PROCEDURE DoLoop;
VAR
i: INTEGER;
BEGIN
i := 0;
WHILE i < LEN(x) DO
Out.Char(x[i]);Out.Char(y[i]);Out.LongInt(z[i],0);Out.Ln;
INC(i)
END
END DoLoop;
BEGIN
x[0] := 'a';y[0] := 'A';z[0] := 1;
x[1] := 'b';y[1] := 'B';z[1] := 2;
x[2] := 'c';y[2] := 'C';z[2] := 3;
DoLoop
END LoopMArrays.
```
Output:
```txt
aA1
bB2
cC3
```
## Objeck
```objeck
class MultipleArrayAccess {
function : Main(args : String[]) ~ Nil {
a := ["a", "b", "c"];
b := ["A", "B", "C"];
c := [1, 2, 3];
each(i : a) {
a[i]->Append(b[i]);
a[i]->Append(c[i]);
a[i]->PrintLine();
};
}
}
```
If the arrays are different lengths,
then an out-of-bounds error will be raised.
## OCaml
an immediate solution:
```ocaml
let a1 = [| 'a'; 'b'; 'c' |]
and a2 = [| 'A'; 'B'; 'C' |]
and a3 = [| '1'; '2'; '3' |] ;;
Array.iteri (fun i c1 ->
print_char c1;
print_char a2.(i);
print_char a3.(i);
print_newline()
) a1 ;;
```
a more generic solution could be to use a function
which iterates over a list of arrays:
```ocaml
let n_arrays_iter ~f = function
| [] -> ()
| x::xs as al ->
let len = Array.length x in
let b = List.for_all (fun a -> Array.length a = len) xs in
if not b then invalid_arg "n_arrays_iter: arrays of different
length";
for i = 0 to pred len do
let ai = List.map (fun a -> a.(i)) al in
f ai
done
```
this function raises Invalid_argument exception if arrays have different
length,
and has this signature:
```ocaml
val n_arrays_iter : f:('a list -> unit) -> 'a
array list -> unit
```
how to use it with arrays a1, a2 and a3 defined before:
```ocaml
let () =
n_arrays_iter [a1; a2; a3] ~f:(fun l ->
List.iter print_char l;
print_newline());
;;
```
## Oforth
If arrays don't have the same size, zipAll reduces to the minimum size
```Oforth
[ "a", "b", "c" ] [ "A", "B", "C" ] [ 1, 2, 3 ]
zipAll(3) apply(#[ apply(#print) printcr ])
```
{{out}}
```txt
aA1
bB2
cC3
```
## ooRexx
```ooRexx
x = .array~of("a", "b", "c")
y = .array~of("A", "B", "C")
z = .array~of(1, 2, 3)
loop i = 1 to x~size
say x[i]y[i]z[i]
end
```
## Oz
```oz
for
I in [a b c]
J in ['A' 'B' 'C']
K in [1 2 3]
do
{System.showInfo I#J#K}
end
```
The loop will stop when the shortest list is exhausted.
## PARI/GP
This version stops when the shortest vector is exhausted.
```parigp
loopMultiple(V)={
my(l=#V[1]);
for(i=2,#V,l=min(l,#V[i]));
for(i=1,#V[1],
for(j=1,#V,
print1(V[j][i])
);
print()
)
};
```
This version prints blanks when a vector is exhausted.
```parigp
loopMultiple(V)={
my(l=0);
for(i=1,#V,l=max(l,#V[i]));
for(i=1,#V[1],
for(j=1,#V,
if(#V[j] $min ? $min : $#$_ for @_;
for my $i(0..$min){ $code->(map $_->[$i] ,@_) }
}
my @a1 = qw( a b c );
my @a2 = qw( A B C );
my @a3 = qw( 1 2 3 );
zip { print @_,"\n" }\(@a1, @a2, @a3);
```
This implementation will stop producing items when the shortest array
ends.
## Perl 6
{{works with|rakudo|2015.12}}
```perl6>for Z ($x, $y, $z) {
say $x, $y, $z;
}
```
The Z operator stops emitting items as soon as the shortest input list is exhausted. However, short lists are easily extended by replicating all or part of the list, or by appending any kind of lazy list generator to supply default values as necessary.
Since Z will return a list of lists (in this example, the first list is ('a', 'A', 1), parentheses are used around in the lambda signature ($x, $y, $z) to unpack the list for each iteration.
### Factoring out concatenation
Note that we can also factor out the concatenation by making the Z metaoperator apply the ~ concatenation operator across each triple:
```perl6>.say for Z~ 1, 2, 3;
```
We could also use the zip-to-string with the reduction metaoperator:
```perl6
.say for [Z~] [], [], [1,2,3]
```
### A list and its indices
The common case of iterating over a list and a list of its indices can be done using the same method:
```perl6
for ^Inf Z -> ($i, $letter) { ... }
```
or by using the .kv (key and value) method on the list (and dropping the parentheses because the list returned by .kv is a flattened list):
```perl6>for $i, $letter { ... }
```
## Phix
Assumes a and b are strings and c is a sequence of integers.
If the arguments were not all the same length, attempts to retrieve non-existent elements would trigger a fatal run-time error.
```Phix
procedure print3(sequence a, b, c)
for i=1 to min({length(a),length(b),length(c)}) do
printf(1, "%s%s%g\n", {a[i], b[i], c[i]})
end for
end procedure
print3("abc","ABC",{1, 2, 3})
```
{{out}}
```txt
aA1
bB2
cC3
```
## PHP
```PHP
$a = array('a', 'b', 'c');
$b = array('A', 'B', 'C');
$c = array('1', '2', '3'); //These don't *have* to be strings, but it
saves PHP from casting them later
if ((sizeOf($a) !== sizeOf($b)) || (sizeOf($b) !== sizeOf($c))){
throw new Exception('All three arrays must be the same length');
}
foreach ($a as $key => $value){
echo "{$a[$key]}{$b[$key]}{$c[$key]}\n";
}
```
This implementation throws an exception if the arrays are not all the
same length.
## PicoLisp
```PicoLisp
(mapc prinl
'(a b c)
'(A B C)
(1 2 3) )
```
The length of the first argument list controls the operation.
If subsequent lists are longer, their remaining values are ignored.
If they are shorter, NIL is passed to the function.
## PL/I
```pli
declare P(3) character (1) initial ('a', 'b', 'c'),
Q(3) character (1) initial ('A', 'B', 'C'),
R(3) fixed decimal (1) initial (1, 2, 3);
do i = lbound(P,1) to hbound(P,1);
put skip edit (P(i), Q(i), R(i)) (2 A, F(1));
end;
```
## PostScript
{{libheader|initlib}}
```postscript
% transpose is defined in initlib like this.
/transpose {
[ exch {
{ {empty? exch pop} map all?} {pop exit} ift
[ exch {} {uncons {exch cons} dip exch} fold counttomark 1 roll]
uncons
} loop ] {reverse} map
}.
% using it.
[[/a /b /c] [/A /B /C] [1 2 3]] transpose
```
## PowerBASIC
```powerbasic
FUNCTION PBMAIN () AS LONG
DIM x(2), y(2) AS STRING * 1
DIM z(2) AS LONG
'data
ARRAY ASSIGN x() = ("a", "b", "c")
ARRAY ASSIGN y() = ("A", "B", "C")
ARRAY ASSIGN z() = (1, 2, 3)
'set upper bound
C& = UBOUND(x)
IF UBOUND(y) > C& THEN C& = UBOUND(y)
IF UBOUND(z) > C& THEN C& = UBOUND(z)
OPEN "output.txt" FOR OUTPUT AS 1
FOR L& = 0 TO C&
IF L& <= UBOUND(x) THEN PRINT #1, x(L&);
IF L& <= UBOUND(y) THEN PRINT #1, y(L&);
IF L& <= UBOUND(z) THEN PRINT #1, TRIM$(STR$(z(L&)));
PRINT #1,
NEXT
CLOSE
END FUNCTION
```
## PowerShell
A cheap and chEasy 'zip' function:
```PowerShell
function zip3 ($a1, $a2, $a3)
{
while ($a1)
{
$x, $a1 = $a1
$y, $a2 = $a2
$z, $a3 = $a3
[Tuple]::Create($x, $y, $z)
}
}
```
```PowerShell
zip3 @('a','b','c') @('A','B','C') @(1,2,3)
```
{{Out}}
```txt
Item1 Item2 Item3
----- ----- -----
a A 1
b B 2
c C 3
```
```PowerShell
zip3 @('a','b','c') @('A','B','C') @(1,2,3) | ForEach-Object {$_.Item1 + $_.Item2 + $_.Item3}
```
{{Out}}
```txt
aA1
bB2
cC3
```
## Prolog
Works with SWI-Prolog
```Prolog
multiple_arrays(L1, L2, L3) :-
maplist(display, L1, L2, L3).
display(A,B,C) :-
writef('%s%s%s\n', [[A],[B],[C]]).
```
{{out}}
```txt
?- multiple_arrays("abc", "ABC", "123").
aA1
bB2
cC3
true.
?- multiple_arrays("abc", "AB", "123").
aA1
bB2
false.
```
## PureBasic
```PureBasic
OpenConsole()
; Fill arrays
Dim a.s(2)
Dim b.s(2)
Dim c(2)
For Arrayposition = 0 To ArraySize(a())
a(Arrayposition) = Chr(Asc("a") + Arrayposition)
b(Arrayposition) = Chr(Asc("A") + Arrayposition)
c(Arrayposition) = Arrayposition + 1
Next
; loop over them
For Arrayposition = 0 To ArraySize(a())
PrintN(a(Arrayposition) + b(Arrayposition) + Str(c(Arrayposition)))
Next
Input() ;wait for Enter before ending
```
If they have different lengths there are two cases:
a() is the shortest one: Only elements up to maximum index of a() are
printed
a() is bigger than another one: if exceeding index to much, program
crashes,
else it may work because there is some "free space" after end of
assigned array memory.
For example if a has size 4, line dD4 will also be printed. size 20
leads to an crash
This is because ReDim becomes slow if everytime there is a change to
array size new memory has to be allocated.
## Python
Using zip():
```python>>>
print ( '\n'.join(''.join(x) for x in
zip('abc', 'ABC', '123')) )
aA1
bB2
cC3
>>>
```
If lists are different lengths, zip() stops after
the shortest one.
Using map():
```python>>>
print(*map(''.join, zip('abc', 'ABC', '123')), sep='\n')
aA1
bB2
cC3
>>>
```
If lists are different lengths, map() in Python 2.x pretends that the shorter lists were extended with
None items; map() in Python 3.x stops after the shortest one.
Using itertools.imap() (Python 2.x):
```python
from itertools import imap
def join3(a,b,c):
print a+b+c
imap(join3,'abc','ABC','123')
```
If lists are differnt lengths, imap() stops after
the shortest is exhausted.
Python 3.X has zip_longest which fills shorter iterables with its
fillvalue argument which defaults to None (similar to the behavior of
''map()'' in Python 2.x):
```python>>>
from itertools import zip_longest
>>> print ( '\n'.join(''.join(x) for x in zip_longest('abc',
'ABCD', '12345', fillvalue='#')) )
aA1
bB2
cC3
#D4
##5
>>>
```
(The Python 2.X equivalent is itertools.izip_longest)
## R
```R
multiloop <- function(...)
{
# Retrieve inputs and convert to a list of character strings
arguments <- lapply(list(...), as.character)
# Get length of each input
lengths <- sapply(arguments, length)
# Loop over elements
for(i in seq_len(max(lengths)))
{
# Loop over inputs
for(j in seq_len(nargs()))
{
# print a value or a space (if that input has finished)
cat(ifelse(i <= lengths[j], arguments[[j]][i], " "))
}
cat("\n")
}
}
multiloop(letters[1:3], LETTERS[1:3], 1:3)
```
Same thing as a single function call.
But throws error if the arrays differ in length.
```R
apply(data.frame(letters[1:3], LETTERS[1:3], 1:3), 1,
function(row) { cat(row, "\n", sep='') })
```
## Racket
Racket for loops can loop over an arbitrary number
of sequences of any kind at once:
```racket
#lang racket
(for ([x '(a b c)] ; list
[y #(A B C)] ; vector
[z "123"]
[i (in-naturals 1)]) ; 1, 2, ... infinitely
(printf "~s: ~s ~s ~s\n" i x y z))
```
The loop stops as soon as the first sequence terminates -- in the above
case i can iterate forever but looping stops when we reach the
end of the list/vector/string. (The same holds for multiple containers
of different sizes.)
## Red
The word repeat evaluates a given block! a specified number of times
and exposes the count value to the block! being executed.
When a variable is used in a path notation, we put a colon in front of it. :counter
```Red>>
blk: [["a" "b" "c"] ["A" "B" "C"] [1 2 3]]
== [["a" "b" "c"] ["A" "B" "C"] [1 2 3]]
>> repeat counter 3 [print [blk/1/:counter blk/2/:counter blk/3/:counter]]
a A 1
b B 2
c C 3
```
## REXX
### same size arrays
If any of the array's elements are missing or it is a short list,
a blank is substituted to retain visual fidelity in the output.
When ''all'' elements are blank, then it signifies the end of the arrays.
```rexx
/*REXX program shows how to simultaneously loop over multiple arrays.*/
x. = ' '; x.1 = "a"; x.2 = 'b'; x.3 = "c"
y. = ' '; y.1 = "A"; y.2 = 'B'; y.3 = "C"
z. = ' '; z.1 = "1"; z.2 = '2'; z.3 = "3"
do j=1 until output=''
output = x.j || y.j || z.j
say output
end /*j*/ /*stick a fork in it, we're done.*/
```
'''output'''
```txt
aA1
bB2
cC3
```
### dissimilar sized arrays
In this example, two of the arrays are extended (past the 1st example).
Also note that REXX doesn't require quotes around non-negative numbers (they're optional).
```rexx
/*REXX program shows how to simultaneously loop over multiple arrays.*/
x.=' '; x.1="a"; x.2='b'; x.3="c"; x.4='d'
y.=' '; y.1="A"; y.2='B'; y.3="C";
z.=' '; z.1= 1 ; z.2= 2 ; z.3= 3 ; z.4= 4; z.5= 5
do j=1 until output=''
output=x.j || y.j || z.j
say output
end /*j*/ /*stick a fork in it, we're done.*/
```
'''output'''
```txt
aA1
bB2
cC3
d 4
5
```
### dissimilar sized lists
```rexx
/*REXX program shows how to simultaneously loop over multiple lists.*/
x = 'a b c d'
y = 'A B C'
z = 1 2 3 4
do j=1 until output=''
output = word(x,j) || word(y,j) || word(z,j)
say output
end /*j*/ /*stick a fork in it, we're done.*/
```
'''output'''
```txt
aA1
bB2
cC3
d4
```
### idiomatic method for lists
```rexx
/*REXX program shows how to simultaneously loop over multiple lists.*/
x = 'a b c d'
y = 'A B C'
z = 1 2 3 4 ..LAST
do j=1 for max(words(x), words(y), words(z))
say word(x,j) || word(y,j) || word(z,j)
end /*j*/ /*stick a fork in it, we're done.*/
```
'''output'''
```txt
aA1
bB2
cC3
d4
..LAST
```
## Ring
```ring
array1 = ["a", "b", "c"]
array2 = ["A", "B", "C"]
array3 = [1, 2, 3]
for n = 1 to 3
see array1[n] + array2[n] + array3[n] + nl
next
```
## Ruby
```ruby
['a','b','c'].zip(['A','B','C'], [1,2,3]) {|i,j,k| puts "#{i}#{j}#{k}"}
```
or
```ruby
['a','b','c'].zip(['A','B','C'], [1,2,3]) {|a| puts a.join}
```
Both of these loops print aA1, bB2, cC3.
Array#zip iterates once for each element of the receiver.
If an argument array is longer, the excess elements are ignored.
If an argument array is shorter, the value nil is supplied.
```ruby
irb(main):001:0> ['a','b','c'].zip(['A','B'], [1,2,3,4]) {|a| puts a.join}
aA1
bB2
c3
=> nil
irb(main):002:0> ['a','b','c'].zip(['A','B'], [1,2,3,4])
=> [["a", "A", 1], ["b", "B", 2], ["c", nil, 3]]
```
## Run BASIC
```runbasic
for i = 1 to 3
a$(i) = chr$(i+96)
b$(i) = chr$(i+64)
c(i) = i
next i
for i = 1 to 3
print a$(i);b$(i);c(i)
next
```
## Rust
```rust
fn main() {
let a1 = ["a", "b", "c"];
let a2 = ["A", "B", "C"];
let a3 = [1, 2, 3];
for ((&x, &y), &z) in a1.iter().zip(a2.iter()).zip(a3.iter()) {
println!("{}{}{}", x, y, z);
}
}
```
{{out}}
```txt
aA1
bB2
cC3
```
## Salmon
```Salmon
// First, we'll define a general-purpose zip() to zip
any
// number of lists together.
function zip(...)
{
variable result;
variable list_num := 0;
iterate(arg; arguments)
{
variable elem_num := 0;
iterate (x; arg)
{
result[elem_num][list_num] := x;
++elem_num;
};
++list_num;
};
return result;
};
immutable a := ["a", "b", "c"],
b := ["A", "B", "C"],
c := [1, 2, 3];
iterate (x; zip(a, b, c))
print(x[0], x[1], x[2], "\n");;
```
The preceding code will throw an exception if the lists aren't the same
length.
Here's an example that will print a number of lines equal to the length
of the longest list and print nothing for elements that are missing if
some lists are shorter than the longest:
```Salmon
// First, we'll define a general-purpose zip() to zip
any
// number of lists together.
function zip(...)
{
variable result := [];
variable list_num := 0;
iterate(arg; arguments)
{
variable elem_num := 0;
iterate (x; arg)
{
if (elem_num >= length(result))
result[elem_num] := <<(* --> "")>>;;
result[elem_num][list_num] := x;
++elem_num;
};
++list_num;
};
return result;
};
immutable a := ["a", "b", "c"],
b := ["A", "B", "C"],
c := [1, 2, 3];
iterate (x; zip(a, b, c))
print(x[0], x[1], x[2], "\n");;
```
## Sather
```sather
class MAIN is
main is
a :ARRAY{STR} := |"a", "b", "c"|;
b :ARRAY{STR} := |"A", "B", "C"|;
c :ARRAY{STR} := |"1", "2", "3"|;
loop i ::= 0.upto!(2);
#OUT + a[i] + b[i] + c[i] + "\n";
end;
end;
end;
```
If the index ''i'' is out of bounds, a runtime error is raised.
## Scala
```scala
("abc", "ABC", "123").zipped foreach { (x, y, z) =>
println(x.toString + y + z)
}
```
## Scheme
Scheme provides for-each and
map to iterate a function over one or more
lists.
The map form is used to collect the results
into a new list.
```scheme
(let ((a '("a" "b" "c"))
(b '("A" "B" "C"))
(c '(1 2 3)))
(for-each
(lambda (i1 i2 i3)
(display i1)
(display i2)
(display i3)
(newline))
a b c))
```
Scheme has a vector datatype with constant-time
retrieval of items held in an ordered sequence. Use srfi-43 to get
similar iterators for vectors, vector-for-each
and vector-map:
```scheme
(let ((a (vector "a" "b" "c"))
(b (vector "A" "B" "C"))
(c (vector 1 2 3)))
(vector-for-each
(lambda (current-index i1 i2 i3)
(display i1)
(display i2)
(display i3)
(newline))
a b c))
```
Note, the lists or vectors must all be of the same length.
## Sidef
The simplest way is by using the Array.zip{} method:
```ruby
[%w(a b c),%w(A B C),%w(1 2 3)].zip { |i,j,k|
say (i, j, k)
}
```
{{out}}
```txt
aA1
bB2
cC3
```
## Smalltalk
{{works with|GNU Smalltalk}}
```smalltalk
|a b c|
a := OrderedCollection new addAll: #('a' 'b' 'c').
b := OrderedCollection new addAll: #('A' 'B' 'C').
c := OrderedCollection new addAll: #(1 2 3).
1 to: (a size) do: [ :i |
(a at: i) display.
(b at: i) display.
(c at: i) displayNl.
].
```
If index ''i'' is out of bound, a runtime error is raised.
## Standard ML
The below code will combine arbitrarily many lists of strings
into a single list with length equal to that of the shortest list.
```Standard ML
(*
* val combine_lists : string list list -> string list
*)
fun combine_lists nil = nil
| combine_lists (l1::ls) = List.foldl (ListPair.map (fn (x,y) => y ^
x)) l1 ls;
(* ["a1Ax","b2By","c3Cz"] *)
combine_lists[["a","b","c"],["1","2","3"],["A","B","C"],["x","y","z"]];
```
## Stata
Use an index variable.
```stata
local u a b c
local v A B C
matrix w=1,2,3
forv i=1/3 {
di "`: word `i' of `u''`: word `i' of `v''`=el("w",1,`i')'"
}
```
### Mata
```stata
mata
u="a","b","c"
v="A","B","C"
w=1,2,3
for (i=1; i<=3; i++) {
printf("%s%s%f\n",u[i],v[i],w[i])
}
end
```
## SuperCollider
Using three variables and indexing (SuperCollider posts the last statement in the REPL)
```SuperCollider
#x, y, z = [["a", "b", "c"], ["A", "B", "C"], ["1", "2", "3"]];
3.collect { |i| x[i] ++ y[i] ++ z[i] }
```
A more idiomatic way of writing it, independent of the number of dimensions:
```SuperCollider
[["a", "b", "c"], ["A", "B", "C"], ["1", "2", "3"]].flop.collect { |x| x.join }
```
Or simpler:
```SuperCollider
[["a", "b", "c"], ["A", "B", "C"], ["1", "2", "3"]].flop.collect(_.join)
```
Same with lamination (a concept from APL/[http://rosettacode.org/wiki/Category:J#The_J_language J]):
```SuperCollider
["a", "b", "c"] +++ ["A", "B", "C"] +++ ["1", "2", "3"]
```
Independent of dimensions:
```SuperCollider
[["a", "b", "c"], ["A", "B", "C"], ["1", "2", "3"]].reduce('+++')
```
## Swift
```Swift
let a1 = ["a", "b", "c"]
let a2 = ["A", "B", "C"]
let a3 = [1, 2, 3]
for i in 0 ..< a1.count {
println("\(a1[i])\(a2[i])\(a3[i])")
}
```
{{out}}
```txt
aA1
bB2
cC3
```
## Tailspin
Simplest iteration with an ordinary "loop" that will error on uneven sizes
```tailspin
def x: ['a', 'b', 'c'];
def y: ['A', 'B', 'C'];
def z: [1, 2, 3];
1..$x::length -> '$x($);$y($);$z($);
' -> !OUT::write
```
{{out}}
```txt
aA1
bB2
cC3
```
A simple transpose method that gives the same output and also errors on uneven sizes
```tailspin
templates transpose
def a: $;
def n: $(1)::length;
[ 1..$n -> $a(1..-1; $) ] !
end transpose
[$x, $y, $z] -> transpose... -> '$...;
' -> !OUT::write
```
A more complex transpose that uses "foreach" more in line with the task proposal and handles uneven arrays
```tailspin
def u: ['a', 'b'];
def v: ['A', 'B', 'C'];
def w: [1];
templates transpose2
@: [];
$... -> [i](
)> ..|@transpose2($i): $;
<> ..|@transpose2: [$];) -> !VOID
$@ !
end transpose2
[$x, $y, $z] -> transpose2... -> '$...;
' -> !OUT::write
'
' -> !OUT::write
[$u,$v,$w] -> transpose2... -> '$...;
' -> !OUT::write
```
{{out}}
```txt
aA1
bB2
cC3
aA1
bB
C
```
## Tcl
```tcl
set list1 {a b c}
set list2 {A B C}
set list3 {1 2 3}
foreach i $list1 j $list2 k $list3 {
puts "$i$j$k"
}
```
If lists are different lengths, the manual
[http://www.tcl.tk/man/tcl8.5/TclCmd/foreach.htm] says:
"The total number of loop iterations is large enough to use up all the
values from all the value lists.
If a value list does not contain enough elements for each of its loop
variables in each iteration, empty values are used for the missing
elements."
## TorqueScript
```Torquescript
$var[0] = "a b c"
$var[1] = "A B C";
$var[2] = "1 2 3";
for(%i=0;%i<3;%i++)
echo(getWord($var[0],%i) @ getWord($var[1],%i) @ getWord($var[2],%i));
```
## TUSCRIPT
```tuscript
$$ MODE TUSCRIPT
arr1="a'b'c"
arr2="a'b'C"
arr3="1'2'3"
LOOP a=arr1,b=arr2,c=arr3
PRINT a,b,c
ENDLOOP
```
{{out}}
```txt
aa1
bb2
cC3
```
## TXR
### Pattern language
```bash
$ txr -c '@(bind a ("a" "b" "c"))
@(bind b ("A" "B" "C"))
@(bind c ("1" "2" "3"))
@(output)
@ (repeat)
@a@b@c
@ (end)
@(end)'
aA1
bB2
cC3
```
===TXR Lisp, using mapcar===
Here we actually loop over four things: three strings and an infinite
list of newlines. The output is built up as one string object that is
finally printed in one go.
```bash
$ txr -e '(pprint (mappend (op list) "abc" "ABC" "123"
(repeat "\n"))))'
aA1
bB2
cC3
```
===TXR Lisp, using each===
```bash
$ txr -e '(each ((x "abc") (y "ABC") (z "123"))
(put-line `@x@y@z`))'
aA1
bB2
cC3
```
### Translation of Scheme
{{trans|Scheme}}
```txrlisp
;; Scheme's vector-for-each: a one-liner in TXR
;; that happily works over strings and lists.
;; We don't need "srfi-43".
(defun vector-for-each (fun . vecs)
[apply mapcar fun (range) vecs])
(defun display (obj : (stream *stdout*))
(pprint obj stream))
(defun newline (: (stream *stdout*))
(display #\newline stream))
(let ((a (vec "a" "b" "c"))
(b (vec "A" "B" "C"))
(c (vec 1 2 3)))
(vector-for-each
(lambda (current-index i1 i2 i3)
(display i1)
(display i2)
(display i3)
(newline))
a b c))
```
### Translation of Logo
{{trans|Logo}}
```txrlisp
(macro-time
(defun question-var-to-meta-num (var)
^(sys:var ,(int-str (cdr (symbol-name var))))))
(defmacro map (square-fun . square-args)
(tree-bind [(fun . args)] square-fun
^[apply mapcar (op ,fun ,*[mapcar question-var-to-meta-num args])
(macrolet ([(. args) ^(quote ,args)])
(list ,*square-args))]))
(defun word (. items)
[apply format nil "~a~a~a" items])
(defun show (x) (pprinl x))
(show (map [(word ?1 ?2 ?3)] [a b c] [A B C] [1 2 3]))
```
{{out}}
```txt
(aA1 bB2 cC3)
```
## UNIX Shell
With the Bourne shell, its for loop (from
[[Loops/Foreach#UNIX Shell]]) can iterate only one list.
We use an index i to access the other lists:
set -- $list loads the positional parameters,
and shift $i moves our element to
$1.
{{works with|Bourne Shell}}
```bash
a=a:b:c
b=A:B:C
c=1:2:3
oldifs=$IFS
IFS=:
i=0
for wa in $a; do
set -- $b; shift $i; wb=$1
set -- $c; shift $i; wc=$1
printf '%s%s%s\n' $wa $wb $wc
i=`expr $i + 1`
done
IFS=$oldifs
```
{{out}}
```txt
aA1
bB2
cC3
```
When the lists have different lengths, this code uses the length of list
a. Longer lists ignore their extra elements,
and shorter lists give extra empty strings.
----
Inspired by the previous example, below is the way to
loop over two arrays simultaneously using set --
$ARGS.
It is less general than the previous example
but it is shorter and works just fine.
{{works with|Bourne Shell}}
```bash
A='a1 a2 a3'
B='b1 b2 b3'
set -- $B
for a in $A
do
printf "$a $1\n"
shift
done
```
{{out}}
```txt
a1 b1
a2 b2
a3 b3
```
----
Some shells have real arrays, so the iteration is much more simple and
easy.
{{works with|bash}}
{{works with|ksh93}}
```bash
a=(a b c)
b=(A B C)
c=(1 2 3)
for ((i = 0; i < ${#a[@]}; i++)); do
echo "${a[$i]}${b[$i]}${c[$i]}"
done
```
{{out}}
```txt
aA1
bB2
cC3
```
{{works with|ksh93}}
{{works with|pdksh}}
```bash
set -A a a b c
set -A b A B C
set -A c 1 2 3
((i = 0))
while ((i < ${#a[@]})); do
echo "${a[$i]}${b[$i]}${c[$i]}"
((i++))
done
```
{{works with|zsh}}
```bash
a=(a b c)
b=(A B C)
c=(1 2 3)
for ((i = 1; i <= $#a; i++)); do
echo "$a[$i]$b[$i]$c[$i]"
done
```
=
## C Shell
=
Uses the length of array ''a''.
Longer arrays ignore their extra elements, but shorter arrays force the
shell to exit with an error like ''b: Subscript out of range.''
```csh
set a=(a b c)
set b=(A B C)
set c=(1 2 3)
@ i = 1
while ( $i <= $#a )
echo "$a[$i]$b[$i]$c[$i]"
@ i += 1
end
```
## Ursa
Looping over multiple arrays in an interactive session:
```ursa>> decl string<
a b c
> append (split "abc" "") a
> append (split "ABC" "") b
> append (split "123" "") c
> for (decl int i) (< i (size a)) (inc i)
.. out a b c endl console
..end
aA1
bB2
cC3
> _
```
If either of the arrays are smaller than (size a), then an indexerror is thrown. This could be caught with a try...catch block.
## Ursala
Compute the transpose of the list formed of the three lists.
If they're of unequal lengths, an exception occurs.
```Ursala
#show+
main = ~&K7 <'abc','ABC','123'>
```
{{out}}
```txt
aA1
bB2
cC3
```
## Visual FoxPro
```vfp
LOCAL i As Integer, n As Integer, c As String
LOCAL ARRAY a1[3], a2[3], a3[4], a[3]
*!* Populate the arrays and store the array lengths in a
a1[1] = "a"
a1[2] = "b"
a1[3] = "c"
a[1] = ALEN(a1)
a2[1] = "A"
a2[2] = "B"
a2[3] = "C"
a[2] = ALEN(a2)
a3[1] = "1"
a3[2] = "2"
a3[3] = "3"
a3[4] = "4"
a[3] = ALEN(a3)
*!* Find the maximum length of the arrays
*!* In this case, 4
n = MAX(a[1], a[2], a[3])
? "Simple Loop"
FOR i = 1 TO n
c = ""
c = c + IIF(i <= a[1], a1[i], "#")
c = c + IIF(i <= a[2], a2[i], "#")
c = c + IIF(i <= a[3], a3[i], "#")
? c
ENDFOR
*!* Solution using a cursor
CREATE CURSOR tmp (c1 C(1), c2 C(1), c3 C(1), c4 C(3))
INSERT INTO tmp (c1, c2, c3) VALUES ("a", "A", "1")
INSERT INTO tmp (c1, c2, c3) VALUES ("b", "B", "2")
INSERT INTO tmp (c1, c2, c3) VALUES ("c", "C", "3")
INSERT INTO tmp (c1, c2, c3) VALUES ("#", "#", "4")
REPLACE c4 WITH c1 + c2 + c3 ALL
? "Solution using a cursor"
LIST OFF FIELDS c4
```
{{out}}
```txt
Simple Loop
aA1
bB2
cC3
##4
Solution using a cursor
aA1
bB2
cC3
##4
```
## Visual Basic .NET
Two implementations: one determines the shortest of the arrays and uses a simple For loop with element accesses to each array separately; one uses Enumerable.Zip (which can only zip two sequences at once) twice to create 3-tuples. Enumerable.Zip stops when either source runs out of elements, so the behavior of the two implementations is identical for arrays of different lengths.
```vbnet
Module Program
Sub Main()
Dim a As Char() = {"a"c, "b"c, "c"c}
Dim b As Char() = {"A"c, "B"c, "C"c}
Dim c As Integer() = {1, 2, 3}
Dim minLength = {a.Length, b.Length, c.Length}.Min()
For i = 0 To minLength - 1
Console.WriteLine(a(i) & b(i) & c(i))
Next
Console.WriteLine()
For Each el As (a As Char, b As Char, c As Integer) In a.Zip(b, Function(l, r) (l, r)).Zip(c, Function(x, r) (x.l, x.r, r))
Console.WriteLine(el.a & el.b & el.c)
Next
End Sub
End Module
```
{{out}}
```txt
aA1
bB2
cC3
aA1
bB2
cC3
```
## Wart
```wart
each (x X n) (zip '(a b c) '(A B C) '(1 2 3))
prn x X n
```
## XPL0
```XPL0
string 0; \use zero terminated strings
include c:\cxpl\codes; \intrinsic 'code' declarations
char A1, A2;
int A3, I;
[A1:= "abc";
A2:= "ABC";
A3:= [1,2,3];
for I:= 0 to 2 do
[ChOut(0, A1(I));
ChOut(0, A2(I));
IntOut(0, A3(I));
CrLf(0);
];
]
```
{{out}}
```txt
aA1
bB2
cC3
```
## zkl
```zkl
foreach a,b,c in (["a".."c"].zip(T("A","B","C"),[1..])){ println(a,b,c) }
```
or
```zkl
Utils.zipWith(False,fcn{vm.arglist.concat().println()},
["a".."c"],T("A","B","C"),[1..])
```
{{out}}
```txt
aA1
bB2
cC3
```
zip[With] stops at the end of the shortest sequence,
which means it can work with infinite sequences
## ZX Spectrum Basic
```zxbasic
10 LET sza = 3: REM size of a
20 LET szb = 3: REM size of b
30 LET szc = 3: REM size of c
40 DIM a$(sza): DIM b$(szb): DIM c$(szc)
50 LET max = sza: REM assume a is the biggest
60 IF szb > max THEN LET max = szb: REM now try b
70 IF szc > max THEN LET max = szc: REM or c
80 REM populate our arrays, and as a bonus we already have our demo loop
90 REM we might as well print as we populate showing the arrays in
columns
100 FOR l = 1 TO max
110 IF l <= sza THEN READ a$(l): PRINT a$(l);
120 IF l <= szb THEN READ b$(l): PRINT b$(l);
130 IF l <= szc THEN READ c$(l): PRINT c$(l);
140 PRINT: REM newline
150 NEXT l
150 PRINT "The arrays are shown in columns."
160 PRINT "A$ runs down the left hand side,"
170 PRINT "and C$ runs down the right."
180 STOP
200 DATA "a","b","c","A","B","C","1","2","3"
```
Simplification
```zxbasic
10 READ size: DIM a$(size): DIM b$(size): DIM c$(size)
20 FOR i=1 TO size
30 READ a$(i),b$(i),c$(i)
40 PRINT a$(i);b$(i);c$(i)
50 NEXT i
60 DATA 3,"a","A","1","b","B","2","c","C","3"
```