in reply to Make array from field of another array

Saved,
I agree that you have done a poor job of explaining. Because you have indicated you can accomplish the job using split, I will assume you have some type of delimited data. That might simply look like: 
my @new_array = split /:/, $old_array[0];

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Then you go on to say iterate which makes me think you want the new array to be the result of all the elements of the old array: 
my @new_array = map {split /:/, $_} @old_array;

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You might also mean something completely different so I would recommend you provide an example of how you are doing it now that you don't care for and see if we can improve upon that.

Cheers - L~R

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Re^2: Make array from field of another array
by Saved (Beadle) on Apr 07, 2011 at 16:25 UTC
    your Code: 
    my @new_array = map {split /:/, $_} @old_array;

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    Is nearly what I was hoping for, but could you do something to get only one field? 
    my @new_array = map {split /:/, ${_[3]}} @old_array;

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[d/l]
[select]
      You can access only one element of the split result by using a list index.

      my @new_array = map { (split /:/)[3] } @old_array;

      Note that I have relied on split's default of splitting $_ when not provided with an explicit string. So the above is exactly equivalent to

      my @new_array = map { (split /:/, $_)[3] } @old_array;

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[d/l]
[select]
        That is it exactly, Thanx very much.
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        That is it exactly, Thanx very much.
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        This appears to work, thanx for your help. 
        #!/usr/bin/perl -w
#<UnusedGrp.pl> Find unused Groups in /etc/group
use strict;

my $GROUPfile="/etc/group";
my $gfpid = open(GFILE, "<$GROUPfile") or die "$GROUPfile File Not Fou
+nd: $!\n";
my $PASSWD="/etc/passwd";
my $pfpid = open(PFILE, "<$PASSWD") or die "$PASSWD File Not Found: $!
+\n";
my @PWLINES = <PFILE>;
my @GIDS = map { (split /:/)[3] } @PWLINES;

while (my $line = <GFILE>) {
   my @GRP = split(/:/, $line);
   if (length($GRP[3]) < 2){
     #print "$GRP[0]:$GRP[2] is zero length\n";
     if ( ! (grep $_ eq $GRP[2], @GIDS)) {
       print "$GRP[0]:$GRP[2] is Empty & not referenced in /etc/passwd
+\n";
     }
   }
}

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[d/l]
Re^2: Make array from field of another array
by Saved (Beadle) on Apr 07, 2011 at 15:52 UTC
    I have updated to post with more detail of what I am trying to do, and some code so far.
[reply]

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