I don't understand the effort to use split and map in solutions.
As the one who first introduced them, I wasn't making any special effort to use split or map. As I (mis)understood the spec, it was the most natural approach to a solution. At a human-level description, if you have a string and want to put brackets around each character, do you search the string for characters and, each time you find one, change it to a three-character sequence of the same character preceded and followed by brackets ($word =~ s/./[$1]/g); or do you consider the text as a list of characters (split '', $word) and put brackets around each of them (map { "[$_]" }, @chars)? Personally, if I were doing it by hand, I'd take the latter approach, and I expect pretty much anyone else would, too.

But, as already pointed out, I misunderstood the spec as wanting to bracket all characters, not only letters. With that limitation in place, the "treat it as a list of characters, not searching in a string" approach still works with a minor modification, and much more simply than the earlier attempts to fix it: 

$new_word = join "", map { $_ =~ /[a-zA-Z]/ ? "[$_]" : $_ } split "", 
+$word;

[download]
Again following the "how would I do it by hand?" approach, this changes the map from "put brackets around each character" to "put brackets around characters in a-zA-Z and leave any other characters as-is", thus transforming "layer123" to "[l][a][y][e][r]123".

In reply to Re^9: regex find and replace with a twist by dsheroh
in thread regex find and replace with a twist by Anonymous Monk

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