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Agreed. In other languages a part of me always feels like if I'm using regex I'm doing something wrong, because I used it so liberally in Perl. It feels like a

Agreed. In other languages a part of me always feels like if I'm using regex I'm doing something wrong, because I used it so liberally in Perl. It feels like a Perl-ism so I try to make a conscious effort not to carry those over as they tend to be the source of inefficiencies.

masklinn 7y ago
TBF for this specific case it's very much unnecessary to break out regexes: most languages do have some sort of literal replacement string API: str.replace = replace(...) S.replace(old, new[, count]) -> str Return a copy of S with all occurrences of substring old replaced by new. If the optional argument count is given, only the first count occurrences are replaced. (though the documentation turns out more misleading than re.sub's: this states it replaces all occurrences but really replaces all non-overlapping occurrences, which re.sub actually spells out properly).
- megaframe 7y ago
  Oddly enough I was asked once to determine if there were any differences between Perl Regex and Python's implementation in an effort to convert a tool I wrote into Python (so other developers could help) I found only one very weird edge case worth noting, in Perl the regex "s/ a* / x /g" (spaces added to prevent formatting) will turn the string "bac" into "xbxxcx" because the "a" technically means zero or more so it matches the spaces between the characters, not so in python it creates the string "xbxcx" because it matched the a in between one time and didn't count the empty spaces. Slightly less accurate results since * does mean zero or more so the space between counts as zero characters.
  - asicsp 7y ago
    That was changed recently, I get 'xbxcx' on 3.5 and 'xbxxcx' on 3.7 And coming to Perl vs Python regex differences, there are too many to count, Python's 3rd party module 'regex' is more comparable to Perl regex. For example, Python doesn't support possesive quantifiers, subexpression calls, \K, \G and so on

masklinn 7y ago

TBF for this specific case it's very much unnecessary to break out regexes: most languages do have some sort of literal replacement string API: str.replace = replace(...) S.replace(old, new[, count]) -> str Return a copy of S with all occurrences of substring old replaced by new. If the optional argument count is given, only the first count occurrences are replaced. (though the documentation turns out more misleading than re.sub's: this states it replaces all occurrences but really replaces all non-overlapping occurrences, which re.sub actually spells out properly).

megaframe 7y ago
Oddly enough I was asked once to determine if there were any differences between Perl Regex and Python's implementation in an effort to convert a tool I wrote into Python (so other developers could help) I found only one very weird edge case worth noting, in Perl the regex "s/ a* / x /g" (spaces added to prevent formatting) will turn the string "bac" into "xbxxcx" because the "a" technically means zero or more so it matches the spaces between the characters, not so in python it creates the string "xbxcx" because it matched the a in between one time and didn't count the empty spaces. Slightly less accurate results since * does mean zero or more so the space between counts as zero characters.
- asicsp 7y ago
  That was changed recently, I get 'xbxcx' on 3.5 and 'xbxxcx' on 3.7 And coming to Perl vs Python regex differences, there are too many to count, Python's 3rd party module 'regex' is more comparable to Perl regex. For example, Python doesn't support possesive quantifiers, subexpression calls, \K, \G and so on