Grepping Key-Value Pairs from Brackets in Perl

Question

What if I have a string that consists of tuples in brackets and I would like to get the maximum value out of the tuple in Perl? Example:

Input: [everyday,32][hoho,16][toodledum,128][echigo,4]

Output: 128

Answer 1

For the input provided:

$input = "[everyday,32][hoho,16][toodledum,128][echigo:4]";
$max = -Inf;
foreach ($input =~ /\[\w+,(\d+)\]/g) {
  $max = $_ if $max < $_;
}
print $max;

Use ([^\]]+) instead of (\d+) if the values might be floating point values.

Answer 2

If you want all of the data, you could put it into a hash first.

my %data = $str =~ /\[([^,]+),([^\]]+)\]/g;
use List::Util qw'max';
my($max) = max(values %data);
print "max: $max\n";

If you want to know which key(s) have that number, you could then use a grep

print "key: $_\n" for grep { $data{$_} == $max } keys %data;

If you really only need the max value:

use List::Util qw'max';
print max $str =~ /\[[^,]+,([^\]]+)\]/g;