perlpal's example was $string =~ s/ {1,}/_/g; which matches a space character while your example $string =~ s/\s+/\_/g; uses the whitespace character class (\s) which matches "\t", "\r", "\n" and "\f" as well as the space character.    In general, the tr/// operator is more efficient then the s/// operator so I try to use it when appropriate.

In reply to Re^3: Regex operation optimisation by jwkrahn
in thread Regex operation optimisation by perlpal

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