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I need to create a formatting documentation. I know the regex that are used to format the text but I don't know how to reproduce an example for that regex. This one should be an internal link:
'{\[((?:\#|/)[^ ]*) ([^]]*)\]}'
Can anyone create an example that would match this, and maybe explain how he got it. I got stuck at '?'.
I never used this meta-character at the beginning, usually I use it to mark that an literal cannot appear or appear exactly once.
Thanks
216
The Escape Symbol : \' etc characters, add a backslash( \ ) before that character. This will tell the computer to treat the following character as a search character and consider it for matching pattern. Example : \d+[\+-x\*]\d+ will match patterns like "2+2" and "3*9" in "(2+2) * 3*9".
Definitions. In formal language theory, a regular expression (a.k.a. regex, regexp, or r.e.), is a string that represents a regular (type-3) language. Huh?? Okay, in many programming languages, a regular expression is a pattern that matches strings or pieces of strings.
Regular expressions are used with the RegExp methods test() and exec() and with the String methods match() , replace() , search() , and split() . Executes a search for a match in a string. It returns an array of information or null on a mismatch. Tests for a match in a string.
(?:...) has the same grouping effect as (...), but without "capturing" the contents of the group; see http://php.net/manual/en/regexp.reference.subpatterns.php.
So, (?:\#|/) means "either # or /".
I'm guessing you know that [^ ]* means "zero or more characters that aren't SP", and that [^]]* means "zero or more characters that aren't right-square-brackets".
Putting it together, one possible string is this:
'{[/abcd asdfasefasdc]}'
See Open source RegexBuddy alternatives and Online regex testing for some helpful tools. It's easiest to have a regex explained by them first. I used YAPE here:
NODE EXPLANATION
----------------------------------------------------------------------
\[ '['
----------------------------------------------------------------------
( group and capture to \1:
----------------------------------------------------------------------
(?: group, but do not capture:
----------------------------------------------------------------------
\# '#'
----------------------------------------------------------------------
| OR
----------------------------------------------------------------------
/ '/'
----------------------------------------------------------------------
) end of grouping
----------------------------------------------------------------------
[^ ]* any character except: ' ' (0 or more
times (matching the most amount
possible))
----------------------------------------------------------------------
) end of \1
----------------------------------------------------------------------
' '
----------------------------------------------------------------------
( group and capture to \2:
----------------------------------------------------------------------
[^]]* any character except: ']' (0 or more
times (matching the most amount
possible))
----------------------------------------------------------------------
) end of \2
----------------------------------------------------------------------
\] ']'
----------------------------------------------------------------------
This is under the presumption that { and } in your example are the regex delimiters.
You can just read through the list of explanations and come up with a possible source string such as:
[#NOSPACE NOBRACKET]
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