View source for Write float arrays to a text file

{{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 should look like:
    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]].
<br><br>

=={{header|Ada}}==
<syntaxhighlight lang="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;</syntaxhighlight>

=={{header|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}}
<syntaxhighlight lang="algol68">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
)</syntaxhighlight> 
{{out}}
<pre>
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
</pre>

=={{header|Amazing Hopper}}==
Version hopper-FLOW:
<syntaxhighlight lang="amazing hopper">
#include <flow.h>

DEF-MAIN(argv,argc)
   
   VOID( x ), MSET( y, f )

   MEM(1,2,3,1.0e11), APND-LST(x), SET( y, x )
   SET-ROUND(5), SQRT(y), MOVE-TO(y)
   UNSET-ROUND
   
   CAT-COLS( f, y, x )
   TOK-SEP( TAB ), SAVE-MAT(f, "filename.txt" )
END
</syntaxhighlight>
{{out}}
<pre>
$ cat filename.txt
1	1
2	1.41421
3	1.73205
1e+11	316228
</pre>

=={{header|Applesoft BASIC}}==
<syntaxhighlight lang="gwbasic"> 100 D$ =  CHR$ (4)
 110 F$ = "FILENAME.TXT"
 120  READ X(0),X(1),X(2),X(3),Y(0),Y(1),Y(2),Y(3)
 130  DATA 1,2,3,1E11
 140  DATA 1,1.4142135623730951,1.7320508075688772,316227.76601683791
 150 XPRECISIO = 3
 160 YPRECISIO = 5
 170  PRINT D$"OPEN"F$
 180  PRINT D$"CLOSE"F$
 190  PRINT D$"DELETE"F$
 200  PRINT D$"OPEN"F$
 210  PRINT D$"WRITE"F$
 220  FOR I = 0 TO 3
 230      P = XPRECISIO:N = X(I): GOSUB 300
 240      PRINT " ";
 250      P = YPRECISIO:N = Y(I): GOSUB 300
 260      PRINT 
 270  NEXT I
 280  PRINT D$"CLOSE"F$
 290  END 
 300 O = N
 310 E = 0
 320  IF O >  = 10 THEN  GOSUB 390
 330  IF O < 1 THEN  GOSUB 450
 340  LET O =  INT ( INT (O * (10 ^ P)) / 10 + .5) / (10 ^ (P - 1))
 350  PRINT O;
 360  IF E > 0 THEN  PRINT "E+" RIGHT$ ("00" +  STR$ (E),3);
 370  IF E < 0 THEN  PRINT "E-" RIGHT$ ("00" +  STR$ ( - E),3);
 380  RETURN 
 390  FOR Q = 0 TO 1
 400      O = O / 10
 410      E = E + 1
 420      Q =  NOT (O >  = 10)
 430  NEXT Q
 440  RETURN 
 450  FOR Q = 0 TO 1
 460      O = O * 10
 470      E = E - 1
 480      Q =  NOT (O < 1)
 490  NEXT Q
 500  RETURN</syntaxhighlight>
=={{header|AWK}}==
As usual, the order of array traversal in AWK is not necessarily the same as the input had:
<syntaxhighlight lang="awk">$ 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</syntaxhighlight>
For the text file part of the task, just redirect stdout to it.

=={{header|BASIC256}}==
<syntaxhighlight lang="basic256">x$ = "1 2 3 1e11"
x$ = explode(x$, " ")

f = freefile
open f, "filename.txt"

for i = 0 to x$[?]-1
	writeline f, int(x$[i]) + chr(9) + round(sqrt(x$[i]),4)
next i
close f</syntaxhighlight>

=={{header|BBC BASIC}}==
{{works with|BBC BASIC for Windows}}
<syntaxhighlight lang="bbcbasic">      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%</syntaxhighlight>
{{out}}
<pre>
1	1
2	1.4142
3	1.7321
1E11	3.1623E5
</pre>

=={{header|C}}==
<syntaxhighlight lang="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;
}</syntaxhighlight>

The file <tt>"floatArray"</tt> then contains the following:
<syntaxhighlight lang="text">1       1
2       1.4142
3       1.7321
1e+11   3.1623e+05</syntaxhighlight>

=={{header|C sharp|C#}}==
<syntaxhighlight lang="csharp">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]);
    }
}</syntaxhighlight>

{{out}}
<pre>1	1
2	1.4142
3	1.7321
1E+11	3.1623E+05</pre>

=={{header|C++}}==
Function ''writedat()'':
<syntaxhighlight lang="cpp">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';
}</syntaxhighlight>
Example:
<syntaxhighlight lang="cpp">#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;
}</syntaxhighlight>

{{out|Result}}
<pre>
1       1
2       1.4142
3       1.7321
1e+11   3.1623e+05
</pre>

=={{header|COBOL}}==
<syntaxhighlight lang="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.
</syntaxhighlight>
{{out|Result}}
<pre>
 1.00E+00   1.0000E+00
 2.00E+00   1.4142E+00
 3.00E+00   1.7321E+00
 1.00E+11   3.1623E+05
</pre>

=={{header|Common Lisp}}==
<syntaxhighlight lang="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)))</syntaxhighlight>
Using [[CLISP]] I get
 1.          1.0000
 2.          1.4142
 3.          1.7321
 1.0E+011    3.16228E+5

=={{header|D}}==
<syntaxhighlight lang="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);
}</syntaxhighlight>
{{out}}
<pre>1	1
2	1.4142
3	1.7321
1e+11	3.1623e+05</pre>
=={{header|Delphi}}==
{{libheader| System.SysUtils}}
{{libheader| System.IoUtils}}
<syntaxhighlight lang="delphi">
program Write_float_arrays_to_a_text_file;

{$APPTYPE CONSOLE}

uses
  System.SysUtils,
  System.IoUtils;

function ToString(v: TArray<Double>): TArray<string>;
var
  fmt: TFormatSettings;
begin
  fmt := TFormatSettings.Create('en-US');
  SetLength(Result, length(v));

  for var i := 0 to High(v) do
    Result[i] := v[i].tostring(ffGeneral, 5, 3, fmt);
end;

function Merge(a, b: TArray<string>): TArray<string>;
begin
  SetLength(Result, length(a));
  for var i := 0 to High(a) do
    Result[i] := a[i] + ^I + b[i];
end;

var
  x, y: TArray<Double>;

begin
  x := [1, 2, 3, 1e11];
  y := [1, 1.4142135623730951, 1.7320508075688772, 316227.76601683791];

  TFile.WriteAllLines('FloatArrayColumns.txt', Merge(ToString(x), ToString(y)));
end.</syntaxhighlight>
{{out}}
<pre>1	1
2	1.4142
3	1.7321
1E011	3.1623E005</pre>

=={{header|Elixir}}==
<syntaxhighlight lang="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)</syntaxhighlight>

{{out}}
<pre>
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
</pre>

=={{header|Erlang}}==
Erlang thinks 1 is an integer. To persuade it otherwise I have to use 1.0.

<syntaxhighlight lang="erlang">
-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 ).
</syntaxhighlight>

{{out}}
<pre>
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">>
</pre>

=={{header|Euphoria}}==
<syntaxhighlight lang="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)</syntaxhighlight>

=={{header|F Sharp|F#}}==
<syntaxhighlight lang="fsharp">[<EntryPoint>]
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</syntaxhighlight>
Content of File, visualized with TAB=8
<pre>1       1
2       1.4142
3       1.7321
1e+11   3.1623e+05</pre>

=={{header|Forth}}==
{{works with|GNU Forth}}

<syntaxhighlight lang="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 ;</syntaxhighlight>

=={{header|Fortran}}==
=== Fortran 90 ===
{{works with|Fortran|90 and later}}
<syntaxhighlight lang="fortran">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</syntaxhighlight>

The arrays x and y should have same bounds (and size); this constraint is not checked.

=== Fortran 77 ===
<syntaxhighlight lang="fortran">      program writefloats
      integer i
      double precision x(4), y(4)
      data x /1d0, 2d0, 4d0, 1d11/

      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</syntaxhighlight>

=={{header|FreeBASIC}}==
<syntaxhighlight lang="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</syntaxhighlight>
Contents of output.txt :
{{out}}
<pre>
1       1.0000
2       1.4142
3       1.7321
1E+11   3.1623E+05
</pre>


=={{header|FutureBasic}}==
<syntaxhighlight lang="futurebasic">
local fn DoIt
  NSUInteger  i
  CFStringRef s
  CFArrayRef  x = @[@1, @2, @3, @1e11]
  CFArrayRef  y = @[@1, @1.4142135623730951, @1.7320508075688772, @316227.76601683791]
  CFMutableStringRef mutStr = fn MutableStringWithCapacity(0)
  
  CFURLRef desktopURL = fn FileManagerURLForDirectory( NSDesktopDirectory, NSUserDomainMask )
  CFURLRef        url = fn URLByAppendingPathComponent( desktopURL, @"Array_to_file.txt" )
  
  for i = 0 to 3
    if ( i < 3 )
      s = fn StringWithFormat( @"%ld    \t", fn NumberIntegerValue( x[i] ) )
      MutableStringAppendString( mutStr, s )
      s = fn StringWithFormat( @"%.4f\n", fn NumberFloatValue( y[i] ) )
      MutableStringAppendString( mutStr, s )
    else
      s = fn StringWithFormat( @"%.e\t", fn NumberFloatValue( x[i] ) )
      MutableStringAppendString( mutStr, s )
      s = fn StringWithFormat( @"%.4e\n", fn NumberFloatValue( y[i] ) )
      MutableStringAppendString( mutStr, s )
    end if
  next
  fn StringWriteToURL( mutStr, url, YES, NSUTF8StringEncoding, NULL )
  print mutStr
end fn

fn DoIt

HandleEven
</syntaxhighlight>
{{output}}
<pre>
1       1.0000
2       1.4142
3       1.7321
1e+11   3.1623e+05
</pre>


=={{header|Go}}==
<syntaxhighlight lang="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()
}</syntaxhighlight>
File contents:
<pre>
1.00e+00, 1.0000e+00
2.00e+00, 1.4142e+00
3.00e+00, 1.7321e+00
1.00e+11, 3.1623e+05
</pre>

=={{header|Haskell}}==
Probably not very idiomatic but oh well
<syntaxhighlight lang="haskell">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</syntaxhighlight>
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
<syntaxhighlight lang="haskell">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</syntaxhighlight>

=={{header|HicEst}}==
<syntaxhighlight lang="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 </syntaxhighlight>
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:
<syntaxhighlight lang="hicest">DLG(Text=x, Format='i12', Edit=y, Format='F10.2', Y=0)</syntaxhighlight>

=={{header|Icon}} and {{header|Unicon}}==

The following works in both languages.

<syntaxhighlight lang="unicon">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</syntaxhighlight>

Contents of <tt>filename</tt> after running:

<pre>
->cat filename
    1.00e0   1.0000e0
    2.00e0   1.4142e0
    3.00e0   1.7321e0
  1.00e+11  3.1623e+5
->
</pre>

=={{header|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 <tt>"datafile.txt"</tt> then contains the following:

<syntaxhighlight lang="idl">1 1
2 1.4142
3 1.7321
1E+011 3.1623E+005</syntaxhighlight>

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.

=={{header|J}}==
<syntaxhighlight lang="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</syntaxhighlight>

Or, more concisely:

<syntaxhighlight lang="j">((0 j. 3 5) ": (,.%:) 1 2 3 1e11) fwrites 'whatever.txt' [ require 'fwrites'</syntaxhighlight>

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":

<syntaxhighlight lang="j">   (0 j. 3 5) ": (,.%:) 1 2 3 1e11
           1.000      1.00000
           2.000      1.41421
           3.000      1.73205
100000000000.000 316227.76602</syntaxhighlight>

=={{header|Java}}==
<syntaxhighlight lang="java5">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) { }
    }
}</syntaxhighlight>

=={{header|Joy}}==
<syntaxhighlight lang="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.
</syntaxhighlight>

Using it:

<pre>
[1.0 2.0 3.0 1e11] 3
[1.0 1.41421356 1.73205080 316227.7660168] 5
write-floats.
</pre>

=={{header|jq}}==
''' Program''':
<syntaxhighlight lang="jq">[1, 2, 3, 1e11] as $x
| $x | map(sqrt) as $y
| range(0; $x|length) as $i
| "\($x[$i])  \($y[$i])"</syntaxhighlight>
''' Execution''':
To write the output to "filename":
<syntaxhighlight lang="sh">$ jq -n -r -f Write_float_arrays_to_a_text_file.jq > filename</syntaxhighlight>

=={{header|Julia}}==
<syntaxhighlight lang="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')</syntaxhighlight>

=={{header|Kotlin}}==
<syntaxhighlight lang="scala">// 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)
        }
    }
}</syntaxhighlight>

Contents of 'output.txt':
<pre>
1.00	1.0000
2.00	1.4142
3.00	1.7321
1.00e+11	3.1623e+05
</pre>

=={{header|Lingo}}==
<syntaxhighlight lang="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</syntaxhighlight>

<syntaxhighlight lang="lingo">x = [1.0, PI, sqrt(2)]
y = [2.0, log(10), sqrt(3)]
saveFloatLists("floats.txt", x, y, 3, 5)</syntaxhighlight>

=={{header|Lua}}==
<syntaxhighlight lang="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 )</syntaxhighlight>

=={{header|M2000 Interpreter}}==
Precision here is just Round (as school rounding)

Print round(2.5,0)=3

Print round(1.5,0)=2

Print round(-2.5,0)=-3

Print round(-1.5,0)=-2

<syntaxhighlight lang="m2000 interpreter">
Module Test1 (filename$, x, xprecision, y, yprecision) {
	locale 1033   // set decimal point symbol  to "."
	// using: for wide output   // for UTF16LE 
	// here we use ANSI (8bit per character)
	open filename$ for output as #f
	for i=0 to len(x)-1
		print #f, format$("{0} {1}", round(x#val(i),xprecision-1), round(y#val(i), yprecision-1))
	next
	close #f
	win "notepad", dir$+filename$
}
Test1 "OutFloat.num", (1, 2, 3, 1.e11),3,  (1, 1.4142135623730951, 1.7320508075688772, 316227.76601683791), 5
</syntaxhighlight>
{{out}}
<pre>1 1
2 1.4142
3 1.7321
100000000000 316227.766</pre>

=={{header|Mathematica}}/{{header|Wolfram Language}}==
<syntaxhighlight lang="mathematica">exportPrec[path_, data1_, data2_, prec1_, prec2_] := 
 Export[
   path,
   Transpose[{Map[ToString[NumberForm[#, prec2]] &, data2], Map[ToString[NumberForm[#, prec1]] &, data1]}],
   "Table"
]</syntaxhighlight>

=={{header|MATLAB}} / {{header|Octave}}==

<syntaxhighlight lang="matlab">    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); </syntaxhighlight>

{{out}}
<pre>1	1
2	1.4142
3	1.7321
1e+11	3.1623e+05</pre>

=={{header|Mercury}}==
<syntaxhighlight lang="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).</syntaxhighlight>

File contents:

<pre>
1              1
2              1.4142
3              1.7321
1e+11      3.1623e+05
</pre>

=={{header|NetRexx}}==
<syntaxhighlight lang="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

-- 08:55, 27 August 2022 (UTC)08:55, 27 August 2022 (UTC)08:55, 27 August 2022 (UTC)08:55, 27 August 2022 (UTC)08:55, 27 August 2022 (UTC)08:55, 27 August 2022 (UTC)08:55, 27 August 2022 (UTC)08:55, 27 August 2022 (UTC)08:55, 27 August 2022 (UTC)08:55, 27 August 2022 (UTC)08:55, 27 August 2022 (UTC)08:55, 27 August 2022 (UTC)08:55, 27 August 2022 (UTC)08:55, 27 August 2022 (UTC)08:55, 27 August 2022 (UTC)~~
-- This function formats the input arrays.
--   It has defaults for the x & y precision values of 3 & 5
-- 08:55, 27 August 2022 (UTC)08:55, 27 August 2022 (UTC)08:55, 27 August 2022 (UTC)08:55, 27 August 2022 (UTC)08:55, 27 August 2022 (UTC)08:55, 27 August 2022 (UTC)08:55, 27 August 2022 (UTC)08:55, 27 August 2022 (UTC)08:55, 27 August 2022 (UTC)08:55, 27 August 2022 (UTC)08:55, 27 August 2022 (UTC)08:55, 27 August 2022 (UTC)08:55, 27 August 2022 (UTC)08:55, 27 August 2022 (UTC)08:55, 27 August 2022 (UTC)~~
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
</syntaxhighlight>
{{out}}
<pre>
1.000           1.00000
2.000           1.41421
3.000           1.73205
1.000E+11       3.16228E+5
</pre>

=={{header|NewLISP}}==
<syntaxhighlight lang="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)</syntaxhighlight>

{{out}}
<pre>File contents:
1          1         
2          1.4142    
3          1.7321    
1e+011     3.1623e+005
</pre>

=={{header|Nim}}==
<syntaxhighlight lang="nim">import strutils, math, sequtils

const OutFileName = "floatarr2file.txt"

const
   XPrecision = 3
   Yprecision = 5

let a = [1.0, 2.0, 3.0, 100_000_000_000.0]
let b = [sqrt(a[0]), sqrt(a[1]), sqrt(a[2]), sqrt(a[3])]
var res = ""
for t in zip(a, b):
    res.add formatFloat(t[0], ffDefault, Xprecision) & "    " &
            formatFloat(t[1], ffDefault, Yprecision) & "\n"

OutFileName.writeFile res
var res2 = OutFileName.readFile()
echo res2</syntaxhighlight>
{{out}}
<pre>1.00    1.0000
2.00    1.4142
3.00    1.7321
1.00e+11    3.1623e+05</pre>

=={{header|OCaml}}==
<syntaxhighlight lang="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</syntaxhighlight>
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 = <abstr>
 # 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 = ()

=={{header|PARI/GP}}==
{{works with|PARI/GP|2.5.0 and above}}
<syntaxhighlight lang="parigp">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))
	)
};</syntaxhighlight>

=={{header|Pascal}}==
<syntaxhighlight lang="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.</syntaxhighlight>
File contents
<pre>
 1.00E+000 1.0000E+000
 2.00E+000 1.4142E+000
 3.00E+000 1.7321E+000
 1.00E+011 3.1623E+005
</pre>

=={{header|Perl}}==
<syntaxhighlight lang="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);</syntaxhighlight>
File contents
<pre>
1	1
2	1.4142
3	1.7321
1e+11	3.1623e+05
</pre>

Alternatively, with the CPAN List::MoreUtils package:

<syntaxhighlight lang="perl">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);</syntaxhighlight>

=={{header|Phix}}==
Copy of [[Write_float_arrays_to_a_text_file#Euphoria|Euphoria]]
<!--<syntaxhighlight lang="phix">-->
 <span style="color: #008080;">constant</span> <span style="color: #000000;">x</span> <span style="color: #0000FF;">=</span> <span style="color: #0000FF;">{</span><span style="color: #000000;">1</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">2</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">3</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">1e11</span><span style="color: #0000FF;">},</span>
          <span style="color: #000000;">y</span> <span style="color: #0000FF;">=</span> <span style="color: #0000FF;">{</span><span style="color: #000000;">1</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">1.4142135623730951</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">1.7320508075688772</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">316227.76601683791</span><span style="color: #0000FF;">}</span>
  
 <span style="color: #004080;">integer</span> <span style="color: #000000;">fn</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">open</span><span style="color: #0000FF;">(</span><span style="color: #008000;">"filename"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"w"</span><span style="color: #0000FF;">)</span>
 <span style="color: #008080;">for</span> <span style="color: #000000;">i</span><span style="color: #0000FF;">=</span><span style="color: #000000;">1</span> <span style="color: #008080;">to</span> <span style="color: #7060A8;">length</span><span style="color: #0000FF;">(</span><span style="color: #000000;">x</span><span style="color: #0000FF;">)</span> <span style="color: #008080;">do</span>
     <span style="color: #7060A8;">printf</span><span style="color: #0000FF;">(</span><span style="color: #000000;">fn</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"%.3g\t%.5g\n"</span><span style="color: #0000FF;">,{</span><span style="color: #000000;">x</span><span style="color: #0000FF;">[</span><span style="color: #000000;">i</span><span style="color: #0000FF;">],</span><span style="color: #000000;">y</span><span style="color: #0000FF;">[</span><span style="color: #000000;">i</span><span style="color: #0000FF;">]})</span>
 <span style="color: #008080;">end</span> <span style="color: #008080;">for</span>
 <span style="color: #7060A8;">close</span><span style="color: #0000FF;">(</span><span style="color: #000000;">fn</span><span style="color: #0000FF;">)</span>
<!--</syntaxhighlight>-->
File contents:
<pre>
1       1
2       1.4142
3       1.7321
1e+11   3.1623e+5
</pre>

=={{header|PicoLisp}}==
An exponential format like "1e11" is not supported
<syntaxhighlight lang="picolisp">(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) )</syntaxhighlight>
{{out}}
<pre>1.000  1.00000
2.000  1.41421
3.000  1.73205</pre>

=={{header|PL/I}}==
<syntaxhighlight lang="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;</syntaxhighlight>
{{out}}
<pre>  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 </pre>

=={{header|PowerShell}}==
<syntaxhighlight lang="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 | Out-String).Trim() > filename.txt  
</syntaxhighlight>
<b>Output:</b>
<pre>
1     1         
2     1.4142    
3     1.7321    
1e+11 3.1623e+05
</pre>

=={{header|PureBasic}}==
<syntaxhighlight lang="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</syntaxhighlight>
{{out}} to text file:
<pre>1.000	1.00000
2.000	1.41421
3.000	1.73205
99999997952.000	316227.75000</pre>

=={{header|Python}}==
{{works with|Python|2.6}}
<syntaxhighlight lang="python">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)</syntaxhighlight>
Example usage
<syntaxhighlight lang="python">>>> 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</syntaxhighlight>

{{works with|Python|3}}
<syntaxhighlight lang="python">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)</syntaxhighlight>

=={{header|R}}==
<syntaxhighlight lang="r">writexy <- function(file, x, y, xprecision=3, yprecision=3) {
  fx <- formatC(x, digits=xprecision, format="g", flag="-")
  fy <- formatC(y, digits=yprecision, format="g", flag="-")
  dfr <- data.frame(fx, fy)
  write.table(dfr, file=file, sep="\t", row.names=F, col.names=F, quote=F)
}

x <- c(1, 2, 3, 1e11)
y <- sqrt(x)
writexy("test.txt", x, y, yp=5)</syntaxhighlight>

=={{header|Racket}}==
<syntaxhighlight lang="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
|#
</syntaxhighlight>

=={{header|Raku}}==
(formerly Perl 6)
===Perl 5-ish===
Written in the style of the 2nd Perl 5 example.
<syntaxhighlight lang="raku" line>sub writefloat ( $filename, @x, @y, $x_precision = 3, $y_precision = 5 ) {
    my $fh = open $filename, :w;
    for flat @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});

writefloat( 'sqrt.dat', @x, @y );</syntaxhighlight>
{{out}}
<pre>1	1
2	1.4142
3	1.7321
1e+11	3.1623e+05</pre>
===Idiomatic===
Written in a more idiomatic style.
<syntaxhighlight lang="raku" line>sub writefloat($filename, @x, @y, :$x-precision = 3, :$y-precision = 3) {
    open($filename, :w).print:
        join '', flat (@x».fmt("%.{$x-precision}g") X "\t") Z (@y».fmt("%.{$y-precision}g") X "\n");
}
my @x = 1, 2, 3, 1e11;
writefloat('sqrt.dat', @x, @x».sqrt, :y-precision(5));</syntaxhighlight>
{{out}}
<pre>1	1
2	1.4142
3	1.7321
1e+11	3.1623e+05</pre>

=={{header|Raven}}==
<syntaxhighlight lang="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</syntaxhighlight>
{{out}}
results.dat file contains:
<pre>1        1
2        1.4142
3        1.7321
1e+11    3.1623e+05</pre>

=={{header|REXX}}==
<syntaxhighlight lang="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.*/</syntaxhighlight>
'''output''' &nbsp; when using the default (internal) data:
<pre>
1    1
2    1.4142
3    1.7321
1e+011    3.1623e+005
</pre>

=={{header|Ring}}==
<syntaxhighlight lang="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)
</syntaxhighlight>
Output:
<pre>
1 | 1
2 | 1.4142135623730
3 | 1.7320508075688
100000000000.0000000000000 | 316227.76601683
</pre>

=={{header|RLaB}}==
In RLaB this task can be done in two ways:

1. 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''.
<syntaxhighlight lang="rlab">
>> x = rand(10,1); y = rand(10,1);
>> writem("mytextfile.txt", [x,y]);
</syntaxhighlight>

2. 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.
<syntaxhighlight lang="rlab">
>> x = rand(10,1); y = rand(10,1);
>> s = text( [x,y], "%10.8f" );
>> writem("mytextfile.txt", s);
</syntaxhighlight>

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.

=={{header|Ruby}}==
<syntaxhighlight lang="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 }</syntaxhighlight>
Result:
<pre>1       1
2       1.4142
3       1.7321
1e+11   3.1623e+05</pre>

=={{header|Run BASIC}}==
<syntaxhighlight lang="runbasic">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</syntaxhighlight>
{{out}}
<pre>             1.000|      1.00000
             2.000|      1.41421
             3.000|      1.73205
  100000000000.000| 316227.76602</pre>

=={{header|SAS}}==
<syntaxhighlight lang="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;</syntaxhighlight>

=={{header|Scala}}==
{{libheader|Scala}}<syntaxhighlight lang="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}")
  }
}</syntaxhighlight>

=={{header|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.<syntaxhighlight lang="seed7">$ 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;</syntaxhighlight>{{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

=={{header|Sidef}}==
{{trans|Raku}}
<syntaxhighlight lang="ruby">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)</syntaxhighlight>
{{out}}
<pre>
1	1
2	1.4142
3	1.7321
1e+11	3.1623e+05
</pre>
=={{header|Smalltalk}}==
{{works with | Smalltalk/X}}
<syntaxhighlight lang="smalltalk">x := #( 1 2 3 1e11 ).
y := x collect:#sqrt.
xprecision := 3.
yprecision := 5.

'sqrt.dat' asFilename writingFileDo:[:fileStream |
    x with:y do:[:xI :yI |
        '%.*g\t%.*g\n' printf:{ xprecision . xI . yprecision . yI } on:fileStream
    ]
]</syntaxhighlight>
obviously, with fix precisions, the following printing expression is more readable:
<syntaxhighlight lang="smalltalk">'%.3g\t%.5g\n' printf:{ xI . yI } on:fileStream</syntaxhighlight>

=={{header|SPL}}==
<syntaxhighlight lang="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)
<</syntaxhighlight>

=={{header|Standard ML}}==
<syntaxhighlight lang="sml">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;</syntaxhighlight>
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

=={{header|Stata}}==

<syntaxhighlight lang="stata">* Create the dataset
clear
mat x=1\2\3\1e11
svmat double x
ren *1 *
gen y=sqrt(x)
format %10.1g x
format %10.5g y

* Save as text file
export delim file.txt, delim(" ") novar datafmt replace</syntaxhighlight>

{{out}}

<pre>1 1
2 1.4142
3 1.7321
1.0e+11 316228</pre>

=={{header|Tcl}}==
<syntaxhighlight lang="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</syntaxhighlight>
{{out}}
<pre>1	1
2	1.4142
3	1.7321
1e+011	3.1623e+005</pre>

=={{header|VBA}}==
<syntaxhighlight lang="vb">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</syntaxhighlight>{{out}}
<pre>1,000E000     1,00000E000
2,000E000     1,41421E000
3,000E000     1,73205E000
1,000E011     3,16228E005
</pre>

=={{header|V (Vlang)}}==
{{incomplete|V (Vlang)|Formatting at least currently doesn't allow variables, floating point notation `g` seems to have bugs}}
<syntaxhighlight lang="v (vlang)">import os
const (
    x = [1.0, 2, 3, 1e11]
    y = [1.0, 1.4142135623730951, 1.7320508075688772, 316227.76601683791]
 
    xprecision = 3
    yprecision = 5
)
 
fn main() {
    if x.len != y.len {
        println("x, y different length")
        return
    }
    mut f := os.create("filename")?
    defer {
        f.close()
    }
    for i,_ in x {
        f.write_string('${x[i]:3}, ${y[i]:1G}\n')?
    }
}</syntaxhighlight>
{{out}}
<pre>  1, 1
  2, 1.414
  3, 1.732
1e+11, 316227.766
</pre>

=={{header|Wren}}==
{{libheader|Wren-fmt}}
In the above module, 'precision' signifies the number of decimal places whereas for the purpose of this task it appears to mean the number of significant figures. We adjust for that by using a precision one less than the required figure.

In the final example, we need to force exponential format as numbers of this size would normally be printed in decimal format.
<syntaxhighlight lang="wren">import "io" for File
import "./fmt" for Fmt

var x = [1, 2, 3, 1e11]
var y = [1, 1.4142135623730951, 1.7320508075688772, 316227.76601683791]
var xprec = 3 - 1 
var yprec = 5 - 1
File.create("filename.txt") { |file|
    for (i in 0...x.count) {
        var f = (i < x.count-1) ? "h" : "e"
        var s  = Fmt.swrite("$0.%(xprec)%(f)\t$0.%(yprec)%(f)\n", x[i], y[i])
        file.writeBytes(s)
    }
}</syntaxhighlight>

{{out}}
The contents of filename.txt:
<pre>
1   	1     
2   	1.4142
3   	1.7321
1e11	3.1623e05
</pre>

=={{header|XPL0}}==
Output is redirected to the file like this: writefloat > filename

Precision here refers to the size of the numeric field. A precision of 5
means a total of five digits, e.g: 1.2345. XPL0 translates this as one place
before the decimal point and four places after it.

<syntaxhighlight lang "XPL0">include xpllib; \for Print
real X, Y;
int  N;
[X:= [1., 2., 3., 1e11];
 Y:= [1., 1.4142135623730951, 1.7320508075688772, 316227.76601683791]; 
 for N:= 0 to 3 do
     Print("%1.2g\t%1.4g\n", X(N), Y(N));
]</syntaxhighlight>
{{out}}
<pre>
1       1
2       1.4142
3       1.7321
1e11    3.1623e5
</pre>

=={{header|Yabasic}}==
<syntaxhighlight lang="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</syntaxhighlight>

=={{header|zkl}}==
<syntaxhighlight lang="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);</syntaxhighlight>
{{out}}
<pre>
$ cat floatArray 
1	1
2	1.4142
3	1.7321
1e+11	3.1623e+05
</pre>

=={{header|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:

<syntaxhighlight lang="zxbasic">SAVE "myarray" DATA g()</syntaxhighlight>