CODEWITHSUNDEEP
regex
codernaut
codernaut

Reputation: 66

Need a RegEx that matches only a single instance of the pipe character

I'm trying to write a RegEx to only match instances of the 'pipe' character (|) that are NOT followed by one or more further pipes. So a pipe followed by anything other than a pipe.

I have this but it doesn't appear to be working:

/|(?!/|)

Upvotes: 3

Views: 1619

Answers (3)

codernaut
codernaut

Reputation: 66

Okay, I found the answer, after much iteration. This will match ONLY a single pipe character not proceeded AND not followed by a pipe.

(?=(\|(?!\|)))((?<!\|)\|)

Upvotes: 1

P O&#39;Conbhui
P O&#39;Conbhui

Reputation: 1223

Match a (start of line or a non-pipe) a pipe (an end of line or a non-pipe).

(^|[^|])[|]([^|]|$)

Upvotes: 0

Rohit Jain
Rohit Jain

Reputation: 213223

You are escaping your pipe wrongly. You need to use backslash, and not slash. Apart from that, you also need to use negative look-behind, so that the last pipe is not matched, which is probably not preceded by a pipe, but not followed by it: -

(?<!\|)\|(?!\|)

Generally, I prefer to use character class rather than escaping if I want to match regex meta-character class: -

(?<![|])[|](?![|])

But, it's my taste.

Upvotes: 5

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