CODEWITHSUNDEEP
regex
jsuissa
jsuissa

Reputation: 1762

Regex matching only words inside custom tag

I'm fairly new to regex and trying to figure out a pattern that will only match the instance of the word inside my custom tag.

In the example below both words match the condition of being after a | and before a ]

Pattern: (?=|)singleline(?=.*])

Sample: [if @sample|singleline second] <p>Another statement singleline goes here</p> [/if]

Upvotes: 1

Views: 284

Answers (2)

Alan Moore
Alan Moore

Reputation: 75222

(?=|) asserts that the next thing in the string either nothing or nothing. That will always evaluate to true; it's always possible to match nothing. I think sweaver2112 is correct that you meant to use a lookbehind there, but you also need to escape the pipe: (?<=\|). Or just match a pipe in the normal way; I don't see any need to use lookarounds for that part.

The other part probably does need to be a lookahead, but you need to expand it a bit. You want to assert that the word is followed by a closing bracket, but not if there's an opening bracket first. Assuming the brackets are always correctly paired, that should mean the word is between a pair of them. Like this:

Pattern: \|singleline(?=[^\]\[]*\])

[^\]\[]*\] matches zero or more of any characters except ] or [, followed by a ]. The backslashes escaping the "real" brackets may or may not be necessary depending on the regex flavor, but escaping them is always safe.

Upvotes: 1

Scott Weaver
Scott Weaver

Reputation: 7351

words that match the condition of being after a | and before a ]

the .*, which means "anything, zero or more times, and be greedy about it", will race to the end of the string and back up only enough to get to a ] (the last one). (and your lookbehind is a lookahead):

if you really want to match what you say you want to match (see quote), then this is it:

Pattern: (?<=|)(\w+)(?=])

Edit: or this one if you want to "match alphanumerics and spaces inside | and ]": 

Pattern: (?<=|)([\w\s]+?)(?=])

Upvotes: 2

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