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
...
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2 Answers
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
3 Comments
zgpmax
Nowadays you should be using the 3-argument form of 'open'. Also you would be better putting your filehandle into a lexical, e.g. "open my $file, '>', 'output.txt' ..."
dgw
@hochgurgler +1 The reason can be found here: stackoverflow.com/questions/1479741/…
Jonah Bishop
@hochgurgler Thanks for the info. I had no idea that a 3-argument form existed, let along that it was a best practice!
If you don't want the foreach loop, you can do this:
print $fh join ("\n", @a);
2 Comments
Sobrique
Your
map is redundant.
Medlock Perlman
@Sobrique: indeed, since the 'join' builtin is already 'loopy'. I've removed it, and ditched the parentheses round join's arguments (pending review).