in reply to Re: Array of Arrays with Variable Names
in thread Array of Arrays with Variable Names

This reply apples to at least two of the above entries, the third I haven't had a chance to address. All of the data is being pulled in from a file of the following structure: 
@array1=(
'entry1',
'entry2',
...
);

@array2=(
'entry1',
'entry2,
...
)

...

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There are a few rules I have to follow here: 1. I can not modify the format of the data file - it is not static, nor do I 'own' it where I can change the way it's generated. 2. The arrays can not be in the script itself . I guess the whole question boils down to this, how can I have the following: 
@combined = ( $opt_f );

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..interpret the following: 
$opt_f = '@array1,@array2'

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As a list of arrays which are then combined, and not simply treat them as regular entries, strings "@array1", "@array2"?

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Re^3: Array of Arrays with Variable Names
by mreece (Friar) on Aug 25, 2006 at 17:39 UTC
    if you absolutely must do it this way, here is how (use eval): 
    ## this is an example, works just as well if these arrays come from a 
+require'd file
my @array1 = qw(a b c);
my @array2 = qw(d e f);

## again, just an example, works just as well if this comes from GetOp
+t
my $opt_f = '@array1, @array2';

## here is the magical and evil eval
my @combined = eval "$opt_f";

print "@combined\n";

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[d/l]
      AHA! Thanks, mreece (and others). That's what I'm looking for - and it's working now. From that suggestion, I've constructed the following snippet which is just a small portion of a much larger work: 
      #!/usr/local/bin/perl5 -w
use Getopt::Std;
require "/path/datafile";
getopts('f:');
chomp $opt_f ;
if ( $opt_f ) {
        @combined =  eval "$opt_f" ;
}
foreach $entry ( @combined )
{
        print "$entry \n";
}

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      Thanks for your patience with a beginner. I read through the warnings about variables in array names before I posted the original post, so I was expecting a lot of people to jump onto that detail... thanks for taking the time to fully understand the problem.
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[d/l]
        one last thing, which i should have mentioned in my previous post. you should check the $@ variable for errors following the eval. consider something like: 
        @combined =  eval "$opt_f" ;
if ($@) {
  die "could not construct a combined array from '$opt_f': $@";
}

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[reply]
[d/l]

      mreece++ (similarly wojtyk below)... at least if we've correctly interpreted the OP's requirements.

      However, since the OP explicitly requested an Array of Arrays, I'd modify the code somewhat (and add a minimum of error checking):

      # Dummy stuff for testing:
my @array1 = qw ( a b c );
my @array2 = qw ( d e f );
my @et_cetera = qw ( etc etc etc );
my $opt_f = '@array1,@array2,@et_cetera';

my @AoA;
for ( split /,/, $opt_f ) {
  my $array_ref = eval '\\' . $_;
  die "Bad input: '$_' doesn't seem to exist!\n" if $@;
  push @AoA, $array_ref;
}
print "@$_\n" for @AoA;

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[d/l]

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