No matter how one reads the totality of your node, there's some sort of disconnect between "an escaped : like \: in which case this would not be split on" and the desired output you show.

And the mismatch in the number of digits (for example, nine "1"s in $string and only 6 in the desired output (that is what the para after the code is, isn't it?) makes it doubly hard to find a single meaning to "would not be split on"

• do you want to keep the \:
• to lose it but keep the second set of "2"s
• to lose both (if so, why six "2"s in the output and only 5 in $string)?

And, just BTW, the colon is NOTescaped in the $string you show; since it's single-quoted, you're showing us a literal backslash followed by a colon.

Perhaps you can clarify.