DOC: re discourage single char class #24123
Conversation
* there are a few cases in the `re` module documentation that suggest "indirectly" escaping single metacharacters by placing them in a character class * in general, this is likely best to avoid because you can incur the overhead of a character class with none of the benefits of a multi-character character class * this is specifically discussed in the more detailed reference cited by the `re` module docs; in particular, see Chapter 6 of: Friedl, Jeffrey. Mastering Regular Expressions. 3rd ed., O’Reilly Media, 2009. * on the topic of using classes to escape metacharacters, which is slightly more justified than single (non-meta)character classes, the author notes `...it's probably because the author didn't know about escaping...` While that may be a little harsh, avoiding the overhead still makes sense to me.
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There is no any overhead, because |
this seemed simple enough not to justify a cognate issue,
but it is a regex matter, so maybe it will need one...
there are a few cases in the
remodule documentationthat suggest "indirectly" escaping single metacharacters
by placing them in a character class; i.e.,
[|]as a viablealternative to
\|in general, this is likely best to avoid because you can
incur the overhead of a character class with none of the
benefits of a multi-character character class
this is specifically discussed in the more detailed
reference cited by the
remodule docs; in particular,see Chapter 6 of:
Friedl, Jeffrey. Mastering Regular Expressions. 3rd ed.,
O’Reilly Media, 2009.
on the topic of using classes to escape metacharacters, which is
slightly more justified than single (non-meta)character classes,
the author notes
...it's probably because the author didn't know about escaping...While that may be a little harsh,
avoiding the overhead still makes sense to me.
the docs already cover the fact that most metacharacters
are deactivated inside character classes, so that general information
is still presented to the user clearly, but now without explicitly
suggesting that the mechanism be used for single (meta)characters