Regular Expressions Advanced Pattern Filtering

Given sufficient time and patients, a lot can be accomplished with pattern filtering

This example swaps columns of a colon-delimited string pair

$myString = "firstname:lastname";
$myString =~ s/([a-z]*):([a-z]*)/\2:\1/i;
# Yields: "lastname:firstname";

The () delimiters means "remember" this part of the pattern

The \# pair means "restore" a numbered part of the pattern