Yes, you're quite correct: when using '/' as a delimiter, you'll need to escape instances of that delimiter in the regex. I should've looked more closely at the delimiters you were using — my apologies.

However, this is true for any delimiter. Here I needed to escape the '-' but not the '/' (with m-...-); with a delimiter not occurring in the regex (e.g. m!...!), no special escapes are required:

$ perl -Mstrict -Mwarnings -le 'my $x = "-"; print $x =~ m-[ /\\-]- ? +1 : 0' Unmatched [ in regex; marked by <-- HERE in m/[ <-- HERE /\\/ at -e l +ine 1. $ perl -Mstrict -Mwarnings -le 'my $x = "-"; print $x =~ m-[ /\\\-]- ? + 1 : 0' 1 $ perl -Mstrict -Mwarnings -le 'my $x = "-"; print $x =~ m![ /\\-]! ? +1 : 0' 1

You may be interested in this (from "perlop: Regexp Quote-Like Operators"):

"If "/" is the delimiter then the initial m is optional. With the m you can use any pair of non-whitespace (ASCII) characters as delimiters. This is particularly useful for matching path names that contain "/", to avoid LTS (leaning toothpick syndrome)." [my emphasis]

-- Ken


In reply to Re^5: getting answer 70 years off by kcott
in thread getting answer 70 years off by derekstucki

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