Question

I have built an array, such as A = [a1,a2,…aN]. How to save this array into a data file, with each element to be placed at one row. In other words, for the array A, the file should look like

a1
a2
a3
...

Answer 1

Very simple (this is assuming, of course, that your array is explicitly specified as an array data structure, which your question doesn’t quite make clear):

#!/usr/bin/perl -w
use strict;

my @a = (1, 2, 3); # The array we want to save

# Open a file named "output.txt"; die if there's an error
open my $fh, '>', "output.txt" or die "Cannot open output.txt: $!";

# Loop over the array
foreach (@a)
{
    print $fh "$_\n"; # Print each entry in our array to the file
}
close $fh; # Not necessary, but nice to do

The above script will write the following to “output.txt”:

1
2
3