Re: How can I use the value of a scalar as the name of an array variable?

[runrig]

One, rather direct, answer: Use symbolic references.

Another, possibly better, answer: Use a hash of arrays instead.

There are a couple issues with using symbolic references for this. One is that symbolic references only work with global variables, so you'll need to declare them with our rather than my. Another is that you'll have to turn off strict refs when accessing the reference. Note that, with this approach, the data file essentially contains variable names! One consequence of this is that if any data row contains a name not declared in your program, you will get a fatal runtime error. Another consequence, which is more of a security hole, is that you could munge your run-time environment if you have a bad data, like

ENV    foo
INC    bar

This program illustrates the symbolic ref approach:

use strict;

our( @fruit, @meat, @dairy );

while (<>)
{
    chomp;
    my( $category, $item ) = split /\t/;
    no strict 'refs';
    push @$category, $item;
}

print "Fruits are: @fruit\n";

The hash-of-arrays approach is safer, and arguably cleaner, though potentially more code-heavy:

use strict;

my %food;

while (<>)
{
    chomp;
    my( $category, $item ) = split /\t/;
    push @{$food{$category}}, $item;
}

print "Fruits are: @{$food{'fruit'}}\n";

Lastly, here's a solution using the hash-of-arrays approach but preserving your desire to put each food item into an array named for the corresponding category. To keep the data clean, the category names are normalized on input, and unrecognized category names are discarded.

use strict;

my( @fruit, @meat, @dairy );

my %food;

$food{'fruit'} = \@fruit;
$food{'meat'}  = \@meat;
$food{'dairy'} = \@dairy;

while (<>)
{
    chomp;
    my( $category, $item ) = split /\t/;
    $category = lc $category; # normalize
    next unless exists $food{$category}; # skip unknown
    push @{$food{$category}}, $item;
}

print "Fruits are: @fruit\n";