Re^3: convert rows to columns

[Athanasius]

No, I did mean =, for assignment.

On each iteration of the while loop, the default variable $_ is implicitly assigned the next line read from the DATA handle. This $_ variable becomes the implicit argument to chomp, and then it’s implicitly bound to the regex match.

So, the code I gave is equivalent to this:

while ($_ = <DATA>)
{
    chomp $_;
    my @pairs = $_ =~ /(..)/g;
    ...

but more compact and “Perlish”. See perlvar#General-Variables.

Hope that helps,