printing to new output files within a loop

Anonymous Monk has asked for the wisdom of the Perl Monks concerning the following question:

Dear Monks,

I have two arrays of equal size and want to simply print an element from each array to a new output file. e.g. $array1[[0]] and $array2[[0]] to a new file etc...

I thought this would work (below) but i'm only creating one new file. Where am I going wrong? Thanks!


for (my $i=0; $i<@array1; $i++)  {
          open (OUT, ">$$.out") or die "can't open OUT\n";
          print OUT ">$array1[$i]>$array2[$i]\n\n\n";
}
[download]

Edit by BazB: add code tags around arrays.

Comment on printing to new output files within a loop Select or Download Code

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Re: printing to new output files within a loop by Old_Gray_Bear (Bishop) on Dec 20, 2004 at 21:01 UTC
Try adding the index to the file name and closing the file inside the loop. Right now you are over-writing the file each time. `for (my $i=0; $i<@array1; $i++) { open (OUT, ">$$.out.$i") or die "can't open OUT\n"; print OUT ">$array1[$i]>$array2[$i]\n\n\n"; close(OUT) or die "Close error on $$.out.$i -- $!\n"; }` [download] ---- I Go Back to Sleep, Now. OGB	[reply] [d/l]
Re: printing to new output files within a loop by Sandy (Curate) on Dec 20, 2004 at 20:59 UTC
the `$$` variable is a process id, which does not change within a currently running process (i.e. execution of your code) If you want a different file name for each iteration, you could construct one using the `$i` variable, as well as the `$$`. Don't forget to close the file after you're done! i.e. `for my $i (0..@array1-1) { open (OUT,">$$.out$i", or die "Ooops...!"; print OUT ">$array1[$i]>$array2[$i]\n\n\n"; close OUT; }` [download]	[reply] [d/l] [select]
Re: printing to new output files within a loop by rir (Vicar) on Dec 20, 2004 at 21:12 UTC
What amw1, Sandy, and Old_Gray_Bear say looks good; but there is also `File::Temp`. Be Well, rir	[reply] [d/l]
Re: printing to new output files within a loop by amw1 (Friar) on Dec 20, 2004 at 20:56 UTC
Looks like you're opening a file named <pid>.out. This may work for you. ($$ is the current process id) `for (my $i = 0 ; $i < @array1 ; $i++) { open(OUT, ">$i.out") or die "can't open $i.out: $!\n"; print OUT ">" . $array1[$i] . ">" . $array2[$i] . "\n\n\n"; close OUT; }` [download]	[reply] [d/l]
Re: printing to new output files within a loop by hostyle (Scribe) on Dec 20, 2004 at 22:11 UTC
Are you sure you didn't mean $_ as opposed to $$ ? $$ Is the pid of your current process which will not change during your loop, hence only one file. $_ is the current default value of your iteration. Or perhaps you meant $i?	[reply]