⚠️ Warning: This is a draft ⚠️
This means it might contain formatting issues, incorrect code, conceptual problems, or other severe issues.
If you want to help to improve and eventually enable this page, please fork RosettaGit's repository and open a merge request on GitHub.
{{task}} [[Category:File_handling]] {{omit from|GUISS}} {{omit from|M4}} {{omit from|Retro|No floating point in standard VM}} {{omit from|UNIX Shell}}
;Task: Write two equal-sized numerical arrays 'x' and 'y' to a two-column text file named 'filename'.
The first column of the file contains values from an 'x'-array with a given 'xprecision', the second -- values from 'y'-array with 'yprecision'.
For example, considering: x = {1, 2, 3, 1e11}; y = {1, 1.4142135623730951, 1.7320508075688772, 316227.76601683791}; /* sqrt(x) */ xprecision = 3; yprecision = 5;
The file is: 1 1 2 1.4142 3 1.7321 1e+011 3.1623e+005
This task is intended as a subtask for [[Measure relative performance of sorting algorithms implementations]].
Ada
with Ada.Text_IO; use Ada.Text_IO;
with Ada.Float_Text_IO; use Ada.Float_Text_IO;
with Ada.Numerics.Elementary_Functions; use Ada.Numerics.Elementary_Functions;
procedure Write_Float_Array is
type Float_Array is array (1..4) of Float;
procedure Write_Columns
( File : File_Type;
X : Float_Array;
Y : Float_Array;
X_Pres : Natural := 3;
Y_Pres : Natural := 5
) is
begin
for I in Float_Array'range loop
Put (File => File, Item => X(I), Fore => 1, Aft => X_Pres - 1);
Put (File, " ");
Put (File => File, Item => Y(I), Fore => 1, Aft => Y_Pres - 1);
New_Line (File);
end loop;
end Write_Columns;
File : File_Type;
X : Float_Array := (1.0, 2.0, 3.0, 1.0e11);
Y : Float_Array;
begin
Put ("Tell us the file name to write:");
Create (File, Out_File, Get_Line);
for I in Float_Array'range loop
Y(I) := Sqrt (X (I));
end loop;
Write_columns (File, X, Y);
Close (File);
end Write_Float_Array;
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 FORMATted transput}}
PROC writedat = (STRING filename, []REAL x, y, INT x width, y width)VOID: (
FILE f;
INT errno = open(f, filename, stand out channel);
IF errno NE 0 THEN stop FI;
FOR i TO UPB x DO
# FORMAT := IF the absolute exponent is small enough, THEN use fixed ELSE use float FI; #
FORMAT repr x := ( ABS log(x[i])<x width | $g(-x width,x width-2)$ | $g(-x width,x width-4,-1)$ ),
repr y := ( ABS log(y[i])<y width | $g(-y width,y width-2)$ | $g(-y width,y width-4,-1)$ );
putf(f, (repr x, x[i], $" "$, repr y, y[i], $l$))
OD;
close(f)
);
# Example usage: #
test:(
[]REAL x = (1, 2, 3, 1e11);
[UPB x]REAL y; FOR i TO UPB x DO y[i]:=sqrt(x[i]) OD;
printf(($"x before:"$, $xg$, x, $l$));
printf(($"y before:"$, $xg$, y, $l$));
writedat("sqrt.dat", x, y, 3+2, 5+2);
printf($"After:"l$);
FILE sqrt dat;
INT errno = open(sqrt dat, "sqrt.dat", stand in channel);
IF errno NE 0 THEN stop FI;
on logical file end(sqrt dat, (REF FILE sqrt dat)BOOL: stop);
TO UPB x DO
STRING line;
get(sqrt dat, (line, new line));
print((line,new line))
OD
)
{{out}}
x before: +1.00000000000000e +0 +2.00000000000000e +0 +3.00000000000000e +0 +1.00000000000000e +11
y before: +1.00000000000000e +0 +1.41421356237310e +0 +1.73205080756888e +0 +3.16227766016838e +5
After:
1.000 1.00000
2.000 1.41421
3.000 1.73205
1e11 316228
AWK
As usual, the order of array traversal in AWK is not necessarily the same as the input had:
$ awk 'BEGIN{split("1 2 3 1e11",x);
> split("1 1.4142135623730951 1.7320508075688772 316227.76601683791",y);
> for(i in x)printf("%6g %.5g\n",x[i],y[i])}'
1e+11 3.1623e+05
1 1
2 1.4142
3 1.7321
For the text file part of the task, just redirect stdout to it.
BBC BASIC
{{works with|BBC BASIC for Windows}}
DIM x(3), y(3)
x() = 1, 2, 3, 1E11
FOR i% = 0 TO 3
y(i%) = SQR(x(i%))
NEXT
xprecision = 3
yprecision = 5
outfile% = OPENOUT("filename.txt")
IF outfile%=0 ERROR 100, "Could not create file"
FOR i% = 0 TO 3
@% = &1000000 + (xprecision << 8)
a$ = STR$(x(i%)) + CHR$(9)
@% = &1000000 + (yprecision << 8)
a$ += STR$(y(i%))
PRINT #outfile%, a$ : BPUT #outfile%, 10
NEXT
CLOSE #outfile%
{{out}}
1 1
2 1.4142
3 1.7321
1E11 3.1623E5
C
#include <stdio.h> #include <math.h> int main(int argc, char **argv) { float x[4] = {1,2,3,1e11}, y[4]; int i = 0; FILE *filePtr; filePtr = fopen("floatArray","w"); for (i = 0; i < 4; i++) { y[i] = sqrt(x[i]); fprintf(filePtr, "%.3g\t%.5g\n", x[i], y[i]); } return 0; }
The file "floatArray" then contains the following:
## C#
```c#
using System.IO;
class Program
{
static void Main(string[] args)
{
var x = new double[] { 1, 2, 3, 1e11 };
var y = new double[] { 1, 1.4142135623730951, 1.7320508075688772, 316227.76601683791 };
int xprecision = 3;
int yprecision = 5;
string formatString = "{0:G" + xprecision + "}\t{1:G" + yprecision + "}";
using (var outf = new StreamWriter("FloatArrayColumns.txt"))
for (int i = 0; i < x.Length; i++)
outf.WriteLine(formatString, x[i], y[i]);
}
}
{{out}}
1 1
2 1.4142
3 1.7321
1E+11 3.1623E+05
C++
Function ''writedat()'':
template<class InputIterator, class InputIterator2> void writedat(const char* filename, InputIterator xbegin, InputIterator xend, InputIterator2 ybegin, InputIterator2 yend, int xprecision=3, int yprecision=5) { std::ofstream f; f.exceptions(std::ofstream::failbit | std::ofstream::badbit); f.open(filename); for ( ; xbegin != xend and ybegin != yend; ++xbegin, ++ybegin) f << std::setprecision(xprecision) << *xbegin << '\t' << std::setprecision(yprecision) << *ybegin << '\n'; }
Example:
#include <algorithm> #include <cmath> // ::sqrt() #include <fstream> #include <iomanip> // setprecision() #include <iostream> #include <string> #include <vector> int main() { try { // prepare test data double x[] = {1, 2, 3, 1e11}; const size_t xsize = sizeof(x) / sizeof(*x); std::vector<double> y(xsize); std::transform(&x[0], &x[xsize], y.begin(), ::sqrt); // write file using default precisions writedat("sqrt.dat", &x[0], &x[xsize], y.begin(), y.end()); // print the result file std::ifstream f("sqrt.dat"); for (std::string line; std::getline(f, line); ) std::cout << line << std::endl; } catch(std::exception& e) { std::cerr << "writedat: exception: '" << e.what() << "'\n"; return 1; } return 0; }
{{out|Result}}
1 1
2 1.4142
3 1.7321
1e+11 3.1623e+05
COBOL
identification division.
program-id. wr-float.
environment division.
input-output section.
file-control.
select report-file assign "float.txt"
organization sequential.
data division.
file section.
fd report-file
report is floats.
working-storage section.
1 i binary pic 9(4).
1 x-values comp-2.
2 value 1.0.
2 value 2.0.
2 value 3.0.
2 value 1.0e11.
1 redefines x-values comp-2.
2 x occurs 4.
1 comp-2.
2 y occurs 4.
report section.
rd floats.
1 float-line type de.
2 line plus 1.
3 column 1 pic -9.99e+99 source x(i).
2 column 12 pic -9.9999e+99 source y(i).
procedure division.
begin.
open output report-file
initiate floats
perform varying i from 1 by 1
until i > 4
compute y(i) = function sqrt (x(i))
generate float-line
end-perform
terminate floats
close report-file
stop run
.
end program wr-float.
{{out|Result}}
1.00E+00 1.0000E+00
2.00E+00 1.4142E+00
3.00E+00 1.7321E+00
1.00E+11 3.1623E+05
Common Lisp
(with-open-file (stream (make-pathname :name "filename") :direction :output) (let* ((x (make-array 4 :initial-contents '(1 2 3 1e11))) (y (map 'vector 'sqrt x)) (xprecision 3) (yprecision 5) (fmt (format nil "~~,1,~d,,G~~12t~~,~dG~~%" xprecision yprecision))) (map nil (lambda (a b) (format stream fmt a b)) x y)))
Using [[CLISP]] I get
1.00001.41421.7321
1.0E+011 3.16228E+5
D
import std.file, std.conv, std.string; void main() { auto x = [1.0, 2, 3, 1e11]; auto y = [1.0, 1.4142135623730951, 1.7320508075688772, 316227.76601683791]; int xPrecision = 3, yPrecision = 5; string tmp; foreach (i, fx; x) tmp ~= format("%." ~ text(xPrecision) ~ "g %." ~ text(yPrecision) ~ "g\r\n", fx, y[i]); write("float_array.txt", tmp); }
{{out}}
1 1
2 1.4142
3 1.7321
1e+11 3.1623e+05
Elixir
defmodule Write_float_arrays do def task(xs, ys, fname, precision\\[]) do xprecision = Keyword.get(precision, :x, 2) yprecision = Keyword.get(precision, :y, 3) format = "~.#{xprecision}g\t~.#{yprecision}g~n" File.open!(fname, [:write], fn file -> Enum.zip(xs, ys) |> Enum.each(fn {x, y} -> :io.fwrite file, format, [x, y] end) end) end end x = [1.0, 2.0, 3.0, 1.0e11] y = for n <- x, do: :math.sqrt(n) fname = "filename.txt" Write_float_arrays.task(x, y, fname) IO.puts File.read!(fname) precision = [x: 3, y: 5] Write_float_arrays.task(x, y, fname, precision) IO.puts File.read!(fname)
{{out}}
1.0 1.00
2.0 1.41
3.0 1.73
1.0e+11 3.16e+5
1.00 1.0000
2.00 1.4142
3.00 1.7321
1.00e+11 3.1623e+5
Erlang
Erlang thinks 1 is an integer. To persuade it otherwise I have to use 1.0.
-module( write_float_arrays ). -export( [task/0, to_a_text_file/3, to_a_text_file/4] ). task() -> File = "afile", Xs = [1.0, 2.0, 3.0, 1.0e11], Ys = [1.0, 1.4142135623730951, 1.7320508075688772, 316227.76601683791], Options = [{xprecision, 3}, {yprecision, 5}], to_a_text_file( File, Xs, Ys, Options ), {ok, Contents} = file:read_file( File ), io:fwrite( "File contents: ~p~n", [Contents] ). to_a_text_file( File, Xs, Ys ) -> to_a_text_file( File, Xs, Ys, [] ). to_a_text_file( File, Xs, Ys, Options ) -> Xprecision = proplists:get_value( xprecision, Options, 2 ), Yprecision = proplists:get_value( yprecision, Options, 2 ), Format = lists:flatten( io_lib:format("~~.~pg ~~.~pg~n", [Xprecision, Yprecision]) ), {ok, IO} = file:open( File, [write] ), [ok = io:fwrite( IO, Format, [X, Y]) || {X, Y} <- lists:zip( Xs, Ys)], file:close( IO ).
{{out}}
3> write_float_arrays:task().
File contents: <<"1.00 1.0000\n2.00 1.4142\n3.00 1.7321\n1.00e+11 3.1623e+5\n">>
Euphoria
constant x = {1, 2, 3, 1e11},
y = {1, 1.4142135623730951, 1.7320508075688772, 316227.76601683791}
integer fn
fn = open("filename","w")
for n = 1 to length(x) do
printf(fn,"%.3g\t%.5g\n",{x[n],y[n]})
end for
close(fn)
=={{header|F Sharp|F#}}==
]
let main argv =
let x = [ 1.; 2.; 3.; 1e11 ]
let y = List.map System.Math.Sqrt x
let xprecision = 3
let yprecision = 5
use file = System.IO.File.CreateText("float.dat")
let line = sprintf "%.*g\t%.*g"
List.iter2 (fun x y -> file.WriteLine (line xprecision x yprecision y)) x y
0
Content of File, visualized with TAB=8
1 1
2 1.4142
3 1.7321
1e+11 3.1623e+05
Forth
{{works with|GNU Forth}}
create x 1e f, 2e f, 3e f, 1e11 f,
create y 1e f, 2e fsqrt f, 3e fsqrt f, 1e11 fsqrt f,
: main
s" sqrt.txt" w/o open-file throw to outfile-id
4 0 do
4 set-precision
x i floats + f@ f.
6 set-precision
y i floats + f@ f. cr
loop
outfile-id stdout to outfile-id
close-file throw ;
Fortran
In ANSI FORTRAN 77 or later use OPEN STATEMENT, and formatted WRITE statement with implied DO loop:
real x(4), y(4)
data x / 1.0, 2.0, 4.0, 1.0e11 /
do 10 i = 1, 4
y = sqrt(x)
10 continue
open(unit=15, file='two_cols.txt', status='new')
write(15,'(f20.3,f21.4)') (x(I), y(I), I = 1, 4)
end
{{works with|Fortran|90 and later}}
program writefloats
implicit none
real, dimension(10) :: a, sqrta
integer :: i
integer, parameter :: unit = 40
a = (/ (i, i=1,10) /)
sqrta = sqrt(a)
open(unit, file="xydata.txt", status="new", action="write")
call writexy(unit, a, sqrta)
close(unit)
contains
subroutine writexy(u, x, y)
real, dimension(:), intent(in) :: x, y
integer, intent(in) :: u
integer :: i
write(u, "(2F10.4)") (x(i), y(i), i=lbound(x,1), ubound(x,1))
end subroutine writexy
end program writefloats
The arrays x and y should have same bounds (and size); this constraint is not checked.
FreeBASIC
' FB 1.05.0 Win64
Dim x(0 To 3) As Double = {1, 2, 3, 1e11}
Dim y(0 To 3) As Double = {1, 1.4142135623730951, 1.7320508075688772, 316227.76601683791}
Open "output.txt" For Output As #1
For i As Integer = 0 To 2
Print #1, Using "#"; x(i);
Print #1, Spc(7); Using "#.####"; y(i)
Next
Print #1, Using "#^^^^"; x(3);
Print #1, Spc(2); Using "##.####^^^^"; y(3)
Close #1
Contents of output.txt : {{out}}
1 1.0000
2 1.4142
3 1.7321
1E+11 3.1623E+05
Go
package main import ( "fmt" "os" ) var ( x = []float64{1, 2, 3, 1e11} y = []float64{1, 1.4142135623730951, 1.7320508075688772, 316227.76601683791} xprecision = 3 yprecision = 5 ) func main() { if len(x) != len(y) { fmt.Println("x, y different length") return } f, err := os.Create("filename") if err != nil { fmt.Println(err) return } for i := range x { fmt.Fprintf(f, "%.*e, %.*e\n", xprecision-1, x[i], yprecision-1, y[i]) } f.Close() }
File contents:
1.00e+00, 1.0000e+00
2.00e+00, 1.4142e+00
3.00e+00, 1.7321e+00
1.00e+11, 3.1623e+05
Haskell
Probably not very idiomatic but oh well
import System.IO import Text.Printf import Control.Monad writeDat filename x y xprec yprec = withFile filename WriteMode $ \h -> -- Haskell's printf doesn't support a precision given as an argument for some reason, so we insert it into the format manually: let writeLine = hPrintf h $ "%." ++ show xprec ++ "g\t%." ++ show yprec ++ "g\n" in zipWithM_ writeLine x y
Example usage Prelude> let x = [1, 2, 3, 1e11] Prelude> let y = map sqrt x Prelude> y [1.0,1.4142135623730951,1.7320508075688772,316227.7660168379] Prelude> writeDat "sqrt.dat" x y 3 5 Prelude> readFile "sqrt.dat" >>= putStr 1.000 1.00000 2.000 1.41421 3.000 1.73205 1.000e11 316227.76602
Alternative solution without Printf
import System.IO import Control.Monad import Numeric writeDat filename x y xprec yprec = withFile filename WriteMode $ \h -> let writeLine a b = hPutStrLn h $ showGFloat (Just xprec) a "" ++ "\t" ++ showGFloat (Just yprec) b "" in zipWithM_ writeLine x y
HicEst
REAL :: n=4, x(n), y(n)
CHARACTER :: outP = "Test.txt"
OPEN(FIle = outP)
x = (1, 2, 3, 1E11)
y = x ^ 0.5
DO i = 1, n
WRITE(FIle=outP, Format='F5, F10.3') x(i), y(i)
ENDDO
Alternative: Display or Edit the formatted arrays in a [http://www.HicEst.com/MatrixExplorer spreadsheet-like dialog] with a common scroll bar. The menu More - Export - File writes the formatted arrays to a file:
DLG(Text=x, Format='i12', Edit=y, Format='F10.2', Y=0)
=={{header|Icon}} and {{header|Unicon}}==
The following works in both languages.
link printf
procedure main()
every put(x := [], (1 to 3) | 1e11)
every put(y := [], sqrt(!x))
every fprintf(open("filename","w"),"%10.2e %10.4e\n", x[i := 1 to *x], y[i])
end
Contents of filename after running:
->cat filename
1.00e0 1.0000e0
2.00e0 1.4142e0
3.00e0 1.7321e0
1.00e+11 3.1623e+5
->
IDL
; the data: x = [1,2,3,1e11] y=sqrt(x) xprecision=3 yprecision=5
; NOT how one would do things in IDL, but in the spirit of the task - the output format: form = string(xprecision,yprecision,format='("(G0.",I0.0,",1x,G0.",I0.0,")")')
; file I/O: openw,unit,"datafile.txt",/get for i = 1L, n_elements(x) do printf, unit, x[i-1],y[i-1],format=form free_lun,unit
The file "datafile.txt" then contains the following:
1 1
2 1.4142
3 1.7321
1E+011 3.1623E+005
This is fairly ugly and un-IDLish. For example one shouldn't just rely on x and y having the same size. And if data is output in human-readable form, it should probably be lined up more nicely. And if it really has to be in two-column format with x and y side by side, one might consider running ASCII_Template or some such instead of that ugly hand-formatting.
J
require 'files' NB. for fwrites
x =. 1 2 3 1e11
y =. %: x NB. y is sqrt(x)
xprecision =. 3
yprecision =. 5
filename =. 'whatever.txt'
data =. (0 j. xprecision,yprecision) ": x,.y
data fwrites filename
Or, more concisely:
((0 j. 3 5) ": (,.%:) 1 2 3 1e11) fwrites 'whatever.txt' [ require 'fwrites'
This loses all of the inline comments and names, and instead relies on the reader's understanding of the purpose of each of the names (for example: 3 is the precision of the first column, and 5 is the precision of the second column).
Note that J's idea of precision here is "positions after the decimal point":
(0 j. 3 5) ": (,.%:) 1 2 3 1e11
1.000 1.00000
2.000 1.41421
3.000 1.73205
100000000000.000 316227.76602
Java
import java.io.*;
public class FloatArray {
public static void writeDat(String filename, double[] x, double[] y,
int xprecision, int yprecision)
throws IOException {
assert x.length == y.length;
PrintWriter out = new PrintWriter(filename);
for (int i = 0; i < x.length; i++)
out.printf("%."+xprecision+"g\t%."+yprecision+"g\n", x[i], y[i]);
out.close();
}
public static void main(String[] args) {
double[] x = {1, 2, 3, 1e11};
double[] y = new double[x.length];
for (int i = 0; i < x.length; i++)
y[i] = Math.sqrt(x[i]);
try {
writeDat("sqrt.dat", x, y, 3, 5);
} catch (IOException e) {
System.err.println("writeDat: exception: "+e);
}
try {
BufferedReader br = new BufferedReader(new FileReader("sqrt.dat"));
String line;
while ((line = br.readLine()) != null)
System.out.println(line);
} catch (IOException e) { }
}
}
Joy
DEFINE write-floats ==
['g 0] [formatf] enconcat map rollup
['g 0] [formatf] enconcat map swap zip
"filename" "w" fopen swap
[[fputchars] 9 fputch] step 10 fputch] step
fclose.
Using it:
[1.0 2.0 3.0 1e11] 3
[1.0 1.41421356 1.73205080 316227.7660168] 5
write-floats.
jq
''' Program''':
[1, 2, 3, 1e11] as $x
| $x | map(sqrt) as $y
| range(0; $x|length) as $i
| "\($x[$i]) \($y[$i])"
''' Execution''': To write the output to "filename":
$ jq -n -r -f Write_float_arrays_to_a_text_file.jq > filename
Julia
xprecision = 3 yprecision = 5 x = round.([1, 2, 3, 1e11],xprecision) y = round.([1, 1.4142135623730951, 1.7320508075688772, 316227.76601683791],yprecision) writedlm("filename", [x y], '\t')
Kotlin
// version 1.1.2 import java.io.File fun main(args: Array<String>) { val x = doubleArrayOf(1.0, 2.0, 3.0, 1e11) val y = doubleArrayOf(1.0, 1.4142135623730951, 1.7320508075688772, 316227.76601683791) val xp = 3 val yp = 5 val f = "%.${xp}g\t%.${yp}g\n" val writer = File("output.txt").writer() writer.use { for (i in 0 until x.size) { val s = f.format(x[i], y[i]) writer.write(s) } } }
Contents of 'output.txt':
1.00 1.0000
2.00 1.4142
3.00 1.7321
1.00e+11 3.1623e+05
Lingo
on saveFloatLists (filename, x, y, xprecision, yprecision)
eol = numtochar(10) -- LF
fp = xtra("fileIO").new()
fp.openFile(tFile, 2)
cnt = x.count
repeat with i = 1 to cnt
the floatPrecision = xprecision
fp.writeString(string(x[i])
fp.writeString(TAB)
the floatPrecision = yprecision
fp.writeString(string(y[i])
fp.writeString(eol)
end repeat
fp.closeFile()
end
x = [1.0, PI, sqrt(2)]
y = [2.0, log(10), sqrt(3)]
saveFloatLists("floats.txt", x, y, 3, 5)
Lua
filename = "file.txt" x = { 1, 2, 3, 1e11 } y = { 1, 1.4142135623730951, 1.7320508075688772, 316227.76601683791 }; xprecision = 3; yprecision = 5; fstr = "%."..tostring(xprecision).."f ".."%."..tostring(yprecision).."f\n" fp = io.open( filename, "w+" ) for i = 1, #x do fp:write( string.format( fstr, x[i], y[i] ) ) end io.close( fp )
Mathematica
exportPrec[path_, data1_, data2_, prec1_, prec2_]:=Export[path,Transpose[{Map[ToString[NumberForm[#, prec2]] &, data2],Map[ToString[NumberForm[#, prec1]] &, data1]}], "Table"]
=={{header|MATLAB}} / {{header|Octave}}==
x = [1, 2, 3, 1e11]; y = [1, 1.4142135623730951, 1.7320508075688772, 316227.76601683791]; fid = fopen('filename','w') fprintf(fid,'%.3g\t%.5g\n',[x;y]); fclose(fid);
{{out}}
1 1
2 1.4142
3 1.7321
1e+11 3.1623e+05
Mercury
:- module write_float_arrays.
:- interface.
:- import_module io.
:- pred main(io::di, io::uo) is det.
:- implementation.
:- import_module float, list, math, string.
main(!IO) :-
io.open_output("filename", OpenFileResult, !IO),
(
OpenFileResult = ok(File),
X = [1.0, 2.0, 3.0, 1e11],
list.foldl_corresponding(write_dat(File, 3, 5), X, map(sqrt, X), !IO),
io.close_output(File, !IO)
;
OpenFileResult = error(IO_Error),
io.stderr_stream(Stderr, !IO),
io.format(Stderr, "error: %s\n", [s(io.error_message(IO_Error))], !IO),
io.set_exit_status(1, !IO)
).
:- pred write_dat(text_output_stream::in, int::in, int::in, float::in,
float::in, io::di, io::uo) is det.
write_dat(File, XPrec, YPrec, X, Y, !IO) :-
io.format(File, "%.*g\t%.*g\n", [i(XPrec), f(X), i(YPrec), f(Y)], !IO).
File contents:
1 1
2 1.4142
3 1.7321
1e+11 3.1623e+05
NetRexx
/* NetRexx */
options replace format comments java crossref savelog symbols nobinary
-- Invent a target text file name based on this program's source file name
parse source . . pgmName '.nrx' .
outFile = pgmName || '.txt'
do
formatArrays(outFile, [1, 2, 3, 1e+11], [1, 1.4142135623730951, 1.7320508075688772, 316227.76601683791])
catch ex = Exception
ex.printStackTrace
end
return
-- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-- This function formats the input arrays.
-- It has defaults for the x & y precision values of 3 & 5
-- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
method formatArrays(outFile, xf = Rexx[], yf = Rexx[], xprecision = 3, yprecision = 5) -
public static signals IllegalArgumentException, FileNotFoundException, IOException
if xf.length > yf.length then signal IllegalArgumentException('Y array must be at least as long as X array')
fw = BufferedWriter(OutputStreamWriter(FileOutputStream(outFile)))
loop i_ = 0 to xf.length - 1
row = xf[i_].format(null, xprecision, null, xprecision).left(15) yf[i_].format(null, yprecision, null, yprecision)
(Writer fw).write(String row)
fw.newLine
end i_
fw.close
return
{{out}}
1.000 1.00000
2.000 1.41421
3.000 1.73205
1.000E+11 3.16228E+5
NewLISP
; file: write-float-array.lsp
; url: http://rosettacode.org/wiki/Write_float_arrays_to_a_text_file
; author: oofoe 2012-01-30
; The "transpose" function is used to flip the joined lists around so
; that it's easier to iterate through them together.
(define (write-float-array x xp y yp filename)
(let ((f (format "%%-10.%dg %%-10.%dg" xp yp))
(o (open filename "write")))
(dolist (v (transpose (list x y)))
(write-line o (format f (v 0) (v 1))))
(close o)
))
; Test
(write-float-array
'(1 2 3 1e11) 3
'(1 1.4142135623730951 1.7320508075688772 316227.76601683791) 5
"filename.chan")
(println "File contents:")
(print (read-file "filename.chan"))
(exit)
{{out}}
File contents:
1 1
2 1.4142
3 1.7321
1e+011 3.1623e+005
Nim
import strutils, math, sequtils const outFileName = "floatarr2file.txt" proc sqrt*(x: int64): float {.importc: "sqrt", header: "<math.h>".} const xprecision = 3 yprecision = 5 var a: seq[int64] = @[int64(1), 2, 3, 100_000_000_000] var b: seq[float] = @[sqrt(a[0]), sqrt(a[1]), sqrt(a[2]), sqrt(a[3])] var c = zip(a,b) var res: string = "" for t in c: res.add($formatFloat(float(t.a),ffDefault,xprecision) & "\t" & $formatFloat(t.b,ffDefault,yprecision) & "\n") writeFile(outFileName,res) var res2 = readFile(outFileName) echo(res2)
{{out}}
1.00 1.0000
2.00 1.4142
3.00 1.7321
1.00e+11 3.1623e+05
OCaml
let write_dat filename x y ?(xprec=3) ?(yprec=5) () = let oc = open_out filename in let write_line a b = Printf.fprintf oc "%.*g\t%.*g\n" xprec a yprec b in List.iter2 write_line x y; close_out oc
Example usage
let x = [1.0; 2.0; 3.0; 1e11];;
val x : float list = [1.; 2.; 3.; 100000000000.]
let y = List.map sqrt x;;
val y : float list = [1.; 1.41421356237309515; 1.73205080756887719; 316227.766016837908]
write_dat "sqrt.dat" x y ();;
- : unit = ()
let ic = open_in "sqrt.dat";;
val ic : in_channel =
try
while true do print_endline (input_line ic) done
with End_of_file -> ();; 1 1 2 1.4142 3 1.7321 1e+11 3.1623e+05
- : unit = ()
PARI/GP
{{works with|PARI/GP|2.5.0 and above}}
f(x,pr)={
Strprintf(if(x>=10^pr,
Str("%.",pr-1,"e")
,
Str("%.",pr-#Str(x\1),"f")
),x)
};
wr(x,y,xprec,yprec)={
for(i=1,#x,
write("filename",f(x[i],xprec),"\t",f(y[i],yprec))
)
};
Pascal
Program WriteNumbers; const x: array [1..4] of double = (1, 2, 3, 1e11); xprecision = 3; yprecision = 5; baseDigits = 7; var i: integer; filename: text; begin assign (filename, 'filename'); rewrite (filename); for i := 1 to 4 do writeln (filename, x[i]:baseDigits+xprecision, sqrt(x[i]):baseDigits+yprecision); close (filename); end.
File contents
1.00E+000 1.0000E+000
2.00E+000 1.4142E+000
3.00E+000 1.7321E+000
1.00E+011 3.1623E+005
Perl
use autodie; sub writedat { my ($filename, $x, $y, $xprecision, $yprecision) = @_; open my $fh, ">", $filename; for my $i (0 .. $#$x) { printf $fh "%.*g\t%.*g\n", $xprecision||3, $x->[$i], $yprecision||5, $y->[$i]; } close $fh; } my @x = (1, 2, 3, 1e11); my @y = map sqrt, @x; writedat("sqrt.dat", \@x, \@y);
File contents
1 1
2 1.4142
3 1.7321
1e+11 3.1623e+05
Alternatively, with the CPAN List::MoreUtils package:
use autodie; use List::MoreUtils qw(each_array); sub writedat { my ($filename, $x, $y, $xprecision, $yprecision) = @_; open my $fh, ">", $filename; my $ea = each_array(@$x, @$y); while ( my ($i, $j) = $ea->() ) { printf $fh "%.*g\t%.*g\n", $xprecision||3, $i, $yprecision||5, $j; } close $fh; } my @x = (1, 2, 3, 1e11); my @y = map sqrt, @x; writedat("sqrt.dat", \@x, \@y);
Perl 6
{{trans|Perl}}
sub writedat ( $filename, @x, @y, $x_precision = 3, $y_precision = 5 ) {
my $fh = open $filename, :w;
for @x Z @y -> $x, $y {
$fh.printf: "%.*g\t%.*g\n", $x_precision, $x, $y_precision, $y;
}
$fh.close;
}
my @x = 1, 2, 3, 1e11;
my @y = @x.map({.sqrt});
writedat( 'sqrt.dat', @x, @y );
File contents
1 1
2 1.4142
3 1.7321
1e+11 3.1623e+05
In Perl 6 Real::base can be used to convert to Str with arbitrary precision and any base you like. Using the hyper-operator >>. let us strip loops, many temporary variables and is a candidate for autothreading.
sub writefloat($filename, @x, @y, :$x-precision = 3, :$y-precision = 5) {
constant TAB = "\t" xx *;
constant NL = "\n" xx *;
open($filename, :w).print(
flat @x>>.base(10, $x-precision) Z TAB Z @y>>.base(10, $y-precision) Z NL);
}
my @x = 1, 2, 3, 1e11;
writefloat('sqrt.dat', @x, @x>>.sqrt, :y-precision(20));
File contents
1.000 1.00000000000000000000
2.000 1.41421356237309510107
3.000 1.73205080756887719318
100000000000.000 316227.76601683790795505047
Phix
Copy of [[Write_float_arrays_to_a_text_file#Euphoria|Euphoria]]
constant x = {1, 2, 3, 1e11},
y = {1, 1.4142135623730951, 1.7320508075688772, 316227.76601683791}
integer fn = open("filename","w")
for i=1 to length(x) do
printf(fn,"%.3g\t%.5g\n",{x[i],y[i]})
end for
close(fn)
File contents:
1 1
2 1.4142
3 1.7321
1e+11 3.1623e+5
PicoLisp
An exponential format like "1e11" is not supported
(setq *Xprecision 3 *Yprecision 5)
(scl 7)
(mapc
'((X Y)
(prinl
(round X *Xprecision)
" "
(round Y *Yprecision) ) )
(1.0 2.0 3.0)
(1.0 1.414213562 1.732050807) )
{{out}}
1.000 1.00000
2.000 1.41421
3.000 1.73205
PL/I
*Process source attributes xref;
aaa: Proc Options(main);
declare X(5) float (9) initial (1, 2, 3, 4, 5),
Y(5) float (18) initial (9, 8, 7, 6, 1e9);
declare (x_precision, y_precision) fixed binary;
Dcl out stream output;
open file(out) title('/OUT.TXT,type(text),recsize(100)');
x_precision = 9;
y_precision = 16;
put file(out) edit((X(i),Y(i) do i=1 to 5))
(skip,e(19,x_precision),
x(2),e(24,y_precision));
end;
{{out}}
1.000000000E+0000 9.0000000000000000E+0000
2.000000000E+0000 8.0000000000000000E+0000
3.000000000E+0000 7.0000000000000000E+0000
4.000000000E+0000 6.0000000000000000E+0000
5.000000000E+0000 1.0000000000000000E+0009
PowerShell
$x = @(1, 2, 3, 1e11) $y = @(1, 1.4142135623730951, 1.7320508075688772, 316227.76601683791) $xprecision = 3 $yprecision = 5 $arr = foreach($i in 0..($x.count-1)) { [pscustomobject]@{x = "{0:g$xprecision}" -f $x[$i]; y = "{0:g$yprecision}" -f $y[$i]} } $arr | format-table -HideTableHeaders > filename.txt
Output:
1 1
2 1.4142
3 1.7321
1e+11 3.1623e+05
PureBasic
#Size = 4
DataSection
Data.f 1, 2, 3, 1e11 ;x values, how many values needed is determined by #Size
EndDataSection
Dim x.f(#Size - 1)
Dim y.f(#Size - 1)
Define i
For i = 0 To #Size - 1
Read.f x(i)
y(i) = Sqr(x(i))
Next
Define file$, fileID, xprecision = 3, yprecision = 5, output$
file$ = SaveFileRequester("Text file for float data", "xydata.txt","Text file | *.txt", 0)
If file$
fileID = OpenFile(#PB_Any, file$)
If fileID
For i = 0 To #Size - 1
output$ = StrF(x(i), xprecision) + Chr(9) + StrF(y(i), yprecision)
WriteStringN(fileID, output$)
Next
CloseFile(fileID)
EndIf
EndIf
{{out}} to text file:
1.000 1.00000
2.000 1.41421
3.000 1.73205
99999997952.000 316227.75000
Python
{{works with|Python|2.6}}
import itertools def writedat(filename, x, y, xprecision=3, yprecision=5): with open(filename,'w') as f: for a, b in itertools.izip(x, y): print >> f, "%.*g\t%.*g" % (xprecision, a, yprecision, b)
Example usage
import math
>>> x = [1, 2, 3, 1e11]
>>> y = map(math.sqrt, x)
>>> y
[1.0, 1.4142135623730951, 1.7320508075688772, 316227.76601683791]
>>> writedat("sqrt.dat", x, y)
>>> # check
...
>>> for line in open('sqrt.dat'):
... print line,
...
1 1
2 1.4142
3 1.7321
1e+011 3.1623e+005
{{works with|Python|3}}
def writedat(filename, x, y, xprecision=3, yprecision=5): with open(filename,'w') as f: for a, b in zip(x, y): print("%.*g\t%.*g" % (xprecision, a, yprecision, b), file=f) #or, using the new-style formatting: #print("{1:.{0}g}\t{3:.{2}g}".format(xprecision, a, yprecision, b), file=f)
R
writexy <- function(file, x, y, xprecision=3, yprecision=3) { #Format inputs as required, and join together fx <- formatC(x, digits=xprecision, format="g", flag="-") fy <- formatC(y, digits=yprecision, format="g", flag="-") dfr <- data.frame(fx, fy) #Write to file. Note that this encloses the formatted number in quotes, write.table(dfr, file=file, sep="\t", row.names=FALSE) #... so we have to process the output str <- readLines(file) writeLines(gsub('"', '', str), file) } x <- c(1, 2, 3, 1e11) y <- sqrt(x) writexy('test.txt', x, y, yp=5)
Racket
#lang racket
(define xs '(1.0 2.0 3.0 1.0e11))
(define ys '(1.0 1.4142135623730951 1.7320508075688772 316227.76601683791))
(define xprecision 3)
(define yprecision 5)
(with-output-to-file "some-file" #:exists 'truncate
(λ() (for ([x xs] [y ys])
(displayln (~a (~r x #:precision xprecision)
" "
(~r y #:precision yprecision))))))
#|
The output is not using exponenets as above, but that's not needed
since Racket can read these numbers fine:
1 1
2 1.41421
3 1.73205
100000000000 316227.76602
|#
Raven
3 as $xprecision
5 as $yprecision
[ ] as $results
[ 1 2 3 1e11 ] as $a
group
$a each sqrt
list as $b
# generate format specifier "%-8.3g %.5g\n"
"%%-8.%($xprecision)dg %%.%($yprecision)dg\n" as $f
define print2 use $v1, $v2, $f
$v2 1.0 prefer $v1 1.0 prefer $f format $results push
4 each as $i
$f $b $i get $a $i get print2
$results "" join "results.dat" write
{{out}} results.dat file contains:
1 1
2 1.4142
3 1.7321
1e+11 3.1623e+05
REXX
/*REXX program writes two arrays to a file with a specified (limited) precision. */
numeric digits 1000 /*allow use of a huge number of digits.*/
oFID= 'filename' /*name of the output File IDentifier.*/
x.=; y.=; x.1= 1 ; y.1= 1
x.2= 2 ; y.2= 1.4142135623730951
x.3= 3 ; y.3= 1.7320508075688772
x.4= 1e11 ; y.4= 316227.76601683791
xPrecision= 3 /*the precision for the X numbers. */
yPrecision= 5 /* " " " " Y " */
do j=1 while x.j\=='' /*process and reformat all the numbers.*/
newX=rule(x.j, xPrecision) /*format X numbers with new precision*/
newY=rule(y.j, yPrecision) /* " Y " " " " */
aLine=translate(newX || left('',4) || newY, "e", 'E')
say aLine /*display re─formatted numbers ──► term*/
call lineout oFID, aLine /*write " " " disk*/
end /*j*/
exit /*stick a fork in it, we're all done. */
/*──────────────────────────────────────────────────────────────────────────────────────*/
rule: procedure; parse arg z 1 oz,p; numeric digits p; z=format(z,,p)
parse var z mantissa 'E' exponent /*get the dec dig exponent*/
parse var mantissa int '.' fraction /* " integer and fraction*/
fraction=strip(fraction, 'T', 0) /*strip trailing zeroes.*/
if fraction\=='' then fraction="."fraction /*any fractional digits ? */
if exponent\=='' then exponent="E"exponent /*in exponential format ? */
z=int || fraction || exponent /*format # (as per rules)*/
if datatype(z,'W') then return format(oz/1,,0) /*is it a whole number ? */
return format(oz/1,,,3,0) /*3 dec. digs in exponent.*/
'''output''' when using the default (internal) data:
1 1
2 1.4142
3 1.7321
1e+011 3.1623e+005
Ring
# Project : Write float arrays to a text file
decimals(13)
x = [1, 2, 3, 100000000000]
y = [1, 1.4142135623730, 1.7320508075688, 316227.76601683]
str = list(4)
fn = "C:\Ring\calmosoft\output.txt"
fp = fopen(fn,"wb")
for i = 1 to 4
str[i] = string(x[i]) + " | " + string(y[i]) + windowsnl()
fwrite(fp, str[i])
next
fclose(fp)
fp = fopen("C:\Ring\calmosoft\output.txt","r")
r = ""
while isstring(r)
r = fgetc(fp)
if r = char(10) see nl
else see r ok
end
fclose(fp)
Output:
1 | 1
2 | 1.4142135623730
3 | 1.7320508075688
100000000000.0000000000000 | 316227.76601683
RLaB
In RLaB this task can be done in two ways:
- Direct writing of the numerical data to the file of an array using function ''writem''. Here the writing format is specified using the global property that is accessible through function ''format''.
>> x = rand(10,1); y = rand(10,1);
>> writem("mytextfile.txt", [x,y]);
- Converting the numerical data to text, and then writing the text to the file, using the same function ''writem''. Here, the writing format is specified through ''text'' function, and the result is written as a plain string matrix.
>> x = rand(10,1); y = rand(10,1);
>> s = text( [x,y], "%10.8f" );
>> writem("mytextfile.txt", s);
Please note, ''writem'' function in RLaB can operate in two-fold fashion. RLaB keeps track of the open files that were created using the built-in function ''open''.
If user writes the data to a file using ''open'' followed by ''writem'' then RLaB opens the file in append mode if it already hasn't been opened. If it has been, then the command ''open'' is ignored (say in batch mode). Then, each successive call to ''writem'' appends newest data to the end of the file while keeping the file open. RLaB will close the file (and OS will flush its file buffer) upon the command ''close''.
If user writes the data to a file by using only ''writem'' then the RLaB temporarily opens the file, writes the data to it, and then closes the file. Successive calls to ''writem'' in this mode will erase the previous content of the file.
Ruby
# prepare test data x = [1, 2, 3, 1e11] y = x.collect { |xx| Math.sqrt xx } xprecision = 3 yprecision = 5 # write the arrays open('sqrt.dat', 'w') do |f| x.zip(y) { |xx, yy| f.printf("%.*g\t%.*g\n", xprecision, xx, yprecision, yy) } end # print the result file open('sqrt.dat', 'r') { |f| puts f.read }
Result:
1 1
2 1.4142
3 1.7321
1e+11 3.1623e+05
Run BASIC
x$ = "1, 2, 3, 1e11"
y$ = "1, 1.4142135623730951, 1.7320508075688772, 316227.76601683791"
open "filename" for output as #f ' Output to "filename"
for i = 1 to 4
print #f, using("##############.###",val(word$(x$,i,",")));"|";using("#######.#####",val(word$(y$,i,",")))
next i
close #f
{{out}}
1.000| 1.00000
2.000| 1.41421
3.000| 1.73205
100000000000.000| 316227.76602
SAS
data _null_;
input x y;
file "output.txt";
put x 12.3 " " y 12.5;
cards;
1 1
2 1.4142135623730951
3 1.7320508075688772
1e11 316227.76601683791
;
run;
Scala
{{libheader|Scala}}
import java.io.{File, FileWriter, IOException} object FloatArray extends App { val x: List[Float] = List(1f, 2f, 3f, 1e11f) def writeStringToFile(file: File, data: String, appending: Boolean = false) = using(new FileWriter(file, appending))(_.write(data)) def using[A <: {def close() : Unit}, B](resource: A)(f: A => B): B = try f(resource) finally resource.close() try { val file = new File("sqrt.dat") using(new FileWriter(file))(writer => x.foreach(x => writer.write(f"$x%.3g\t${math.sqrt(x)}%.5g\n"))) } catch { case e: IOException => println(s"Running Example failed: ${e.getMessage}") } }
Seed7
The library [http://seed7.sourceforge.net/libraries/math.htm math.s7i] defines the function [http://seed7.sourceforge.net/libraries/math.htm#sqrt%28ref_float%29 sqrt]. The operators [http://seed7.sourceforge.net/libraries/float.htm#%28ref_float%29sci%28ref_integer%29 sci] and [http://seed7.sourceforge.net/libraries/float.htm#%28in_string%29exp%28in_integer%29 exp] (defined in [http://seed7.sourceforge.net/libraries/float.htm float.s7i]) support writing floating point numbers in scientific notation.
$ include "seed7_05.s7i";
include "float.s7i";
include "math.s7i";
const proc: main is func
local
const array float: numbers is [] (1.0, 2.0, 3.0, 1.0e11);
var float: aFloat is 0.0;
var file: aFile is STD_NULL;
begin
aFile := open("filename", "w");
for aFloat range numbers do
writeln(aFile, aFloat sci 3 exp 2 <& " " <& sqrt(aFloat) sci 5 exp 2);
end for;
close(aFile);
end func;
{{out|Result file ''filename''}} 1.000e+00 1.00000e+00 2.000e+00 1.41421e+00 3.000e+00 1.73205e+00 1.000e+11 3.16228e+05
Sidef
{{trans|Perl 6}}
func writedat(filename, x, y, x_precision=3, y_precision=5) { var fh = File(filename).open_w for a,b in (x ~Z y) { fh.printf("%.*g\t%.*g\n", x_precision, a, y_precision, b) } fh.close } var x = [1, 2, 3, 1e11] var y = x.map{.sqrt} writedat('sqrt.dat', x, y)
{{out}}
1 1
2 1.4142
3 1.7321
1e+11 3.1623e+05
SPL
x = [1, 2, 3, 10^11]
y = [1, 1.4142135623730951, 1.7320508075688772, 316227.76601683791]
xprecision = 3
yprecision = 5
> i, 1..4
s1 = #.str(x[i],"g"+xprecision)
s2 = #.str(y[i],"g"+yprecision)
#.writeline("file.txt",s1+#.tab+s2)
<
Standard ML
fun writeDat (filename, x, y, xprec, yprec) = let
val os = TextIO.openOut filename
fun write_line (a, b) =
TextIO.output (os, Real.fmt (StringCvt.GEN (SOME xprec)) a ^ "\t" ^
Real.fmt (StringCvt.GEN (SOME yprec)) b ^ "\n")
in
ListPair.appEq write_line (x, y);
TextIO.closeOut os
end;
Example usage
- val x = [1.0, 2.0, 3.0, 1e11]; val x = [1.0,2.0,3.0,100000000000.0] : real list
- val y = map Math.sqrt x; val y = [1.0,1.41421356237,1.73205080757,316227.766017] : real list
- writeDat ("sqrt.dat", x, y, 3, 5); val it = () : unit
- val is = TextIO.openIn "sqrt.dat"; val is = - : TextIO.instream
- print (TextIO.inputAll is); 1.0 1.0 2.0 1.4142 3.0 1.7321 1E11 3.1623E05 val it = () : unit
Tcl
set x {1 2 3 1e11} foreach a $x {lappend y [expr {sqrt($a)}]} set fh [open sqrt.dat w] foreach a $x b $y { puts $fh [format "%.*g\t%.*g" $xprecision $a $yprecision $b] } close $fh set fh [open sqrt.dat] puts [read $fh [file size sqrt.dat]] close $fh
{{out}}
1 1
2 1.4142
3 1.7321
1e+011 3.1623e+005
VBA
Public Sub main()
x = [{1, 2, 3, 1e11}]
y = [{1, 1.4142135623730951, 1.7320508075688772, 316227.76601683791}]
Dim TextFile As Integer
TextFile = FreeFile
Open "filename" For Output As TextFile
For i = 1 To UBound(x)
Print #TextFile, Format(x(i), "0.000E-000"), Format(y(i), "0.00000E-000")
Next i
Close TextFile
End Sub
{{out}}
1,000E000 1,00000E000
2,000E000 1,41421E000
3,000E000 1,73205E000
1,000E011 3,16228E005
Yabasic
x$ = "1 2 3 1e11"
pr1 = 3 : pr2 = 5
dim x$(1)
n = token(x$, x$())
f = open("filename.txt", "w")
for i = 1 to n
print #f str$(val(x$(i)), "%1." + str$(pr1) + "g") + "\t" + str$(sqrt(val(x$(i))), "%1." + str$(pr2) + "g")
next i
close #f
zkl
fcn writeFloatArraysToFile(filename, xs,xprecision, ys,yprecision){
f :=File(filename,"w");
fmt:="%%.%dg\t%%.%dg".fmt(xprecision,yprecision).fmt; // "%.3g\t%.5g".fmt
foreach x,y in (xs.zip(ys)){ f.writeln(fmt(x,y)); }
f.close();
}
xs,ys := T(1.0, 2.0, 3.0, 1e11), xs.apply("sqrt");
xprecision,yprecision := 3,5;
writeFloatArraysToFile("floatArray.txt", xs,xprecision, ys,yprecision);
{{out}}
$ cat floatArray
1 1
2 1.4142
3 1.7321
1e+11 3.1623e+05
ZX Spectrum Basic
The ZX Spectrum has a dedicated file format for floating point arrays. Although this format is not a text file, it would be the usual format for writing such data to a file on a ZX Spectrum. Here we write the contents of the array g() to a file:
SAVE "myarray" DATA g()