Re: Regex: match a word stem plus an optional suffix from a group

Maybe I'm misunderstanding the problem ...

... but this works for me, if your "placeholder" is a variable starting with $ .

> perl -de0
...
  DB<1> @a = qw(Russia Russia's Russias Russian)

  DB<2> $wordstem = "Russia"

  DB<3> x grep { /\bwordstem(s|\'s|n)?\b/i } @a
  empty array

  DB<4> x grep { /\b$wordstem(s|\'s|n)?\b/i } @a
0  'Russia'
1  'Russia\'s'
2  'Russias'
3  'Russian'
[download]

Cheers Rolf
_{(addicted to the Perl Programming Language :)

Wikisyntax for the Monastery}

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Re^2: Regex: match a word stem plus an optional suffix from a group by element22 (Novice) on Jul 21, 2022 at 02:13 UTC
Thanks, I found the typo: in my regex, the last suffix was "an" not just "n", so it didn't match "Russian". Now it does. Yes, my variable starts with a $. Now I also put it in squiggly brackets for clarity ${wordstem}.	[reply]
Re^3: Regex: match a word stem plus an optional suffix from a group by Your Mother (Archbishop) on Jul 21, 2022 at 02:40 UTC
You should also escape interpolated stuff in regexen. `\Q${wordstem}\E` in this case. If you don’t, you can end up with really confusing bugs and, depending on Perl version, a malicious regex that can be a DoS attack. I would encourage you to use `/x` to improve readability. Something like– `/ \b \Q${stem}\E (?: s \| 's \| n )? \b /xi` [download]	[reply] [d/l] [select]