I am new to regular expressions and have been given the following regular expression:
(\p{L}|\p{N}|_|-|\.)*
I know what * means and | means "or" and that \ escapes.
But what I don't know what \p{L} and \p{N} means. I have searched Google for it, without result...
Can someone help me?
This question is related to
xml
regex
character-class
\p{L}matches a single code point in the category "letter".
\p{N}matches any kind of numeric character in any script.
Source: regular-expressions.info
If you're going to work with regular expressions a lot, I'd suggest bookmarking that site, it's very useful.
These are Unicode property shortcuts (\p{L} for Unicode letters, \p{N} for Unicode digits). They are supported by .NET, Perl, Java, PCRE, XML, XPath, JGSoft, Ruby (1.9 and higher) and PHP (since 5.1.0)
At any rate, that's a very strange regex. You should not be using alternation when a character class would suffice:
[\p{L}\p{N}_.-]*
Source: Stackoverflow.com