Wow... When I started working on this there were no posts. Now there's 3.

Well I'll post my own solution also, though I think I've already been outdone.

My approach is simple. First split on the space to an array & then iterate over it looking for '='

When it's found, assign to that key. Every value that follows is assumed to belong to that key until another is mentioned.

You did say the purpose here was to assign multiple values an an individual key, yes?

Well then assuming that your values don't contain commas, you could do something similar when extracting. Test for a ',' & if it exisits, split on it.

Anyway, here's my effort, I hope it helps:

#!e:\perl\bin\perl.exe -w

use strict;

my $data="key1=value1 key2=value2 value3 key4=value4 value5 value6 key
+5=value7 key6=value8 key7=value9 value10";



my @values=split(/ /,$data);
my ($h,$value, $v, $recentkey);
my %output;
my @hashkeys;


for $value(@values) {
        if ($value =~ /=/) {
                ($recentkey, $v) = split(/=/,$value);
                $output{$recentkey} = $v;
        } else {
                $output{$recentkey} .= ",$v";
        }
}

@hashkeys = keys %output;
for $h(@hashkeys) {
        print "$h: $output{$h} \n";
}
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Wait! This isn't a Parachute, this is a Backpack!