Regex: Finding strings that doesn't start with X

Question

I am completely hopeless with regular expressions...

I have a Velocimacro named #addButton, and I have a JS function named addButton(). Now I want to find all the places the JS function is called. So I need to search for "addButton", where "addButton" doesn't start with the hash key.

Any ideas?

Scott Coldwell · Accepted Answer · 2017-05-24 22:26:24Z

24

I don't know what Velocimacro is (judging from the other answer I guess "addButton" will appear on its own line?), but the sure-fire way of finding the word "addButton" that is not preceeded by # is the following:

/(?<!#)\baddButton\b/

It will:

(?<!#) (?)
- Make sure that the current position is not preceeded by a # (hash mark)
\b (?)
- Make sure that the current position is a word boundary (in this case it makes sure that the previous character is not a word character and that the next character is)
addButton (?)
- Match "addButton"
\b (?)
- Make sure that there is a word boundary at the current position. This avoids matching things like "addButtonNew" (because there is no word boundary between "addButton" and "New")

A difference with this regular expression and the other is that this one will not consume the character before "addButton".

A good resource for learning about regular expressions is regular-expressions.info. Click the (?) link in the list above for a link to the relevant page for that part of the regex.

edited May 24, 2017 at 22:26

Scott Coldwell

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answered Aug 12, 2009 at 6:59

Blixt

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2 Comments

peirix Over a year ago

excellent informative answer. thanks! (: I was just doing a regex search in Eclipse, so consuming characters doesn't matter. (btw, Velocimacro is sorta like a function in Velocity (open source templating language), and you call them like normal functions, only every command in Velocity starts with the hash key)

nanobar Over a year ago

Thanks, how can I say "Don't match #, including if followed by any number of spaces?"

Adam Byrtek · Accepted Answer · 2009-08-12 06:54:37Z

13

/([^#]|^)addButton/

It will match every string where "addButton" is not preceded by "#" or the beginning of the string.

edited Aug 12, 2009 at 6:54

answered Aug 12, 2009 at 6:48

Adam Byrtek

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2 Comments

Amber Over a year ago

Or to make it a little more robust (so that it will match at the beginning of a string), /(?:^|[^#])addButton/

peirix Over a year ago

awesome! ... I think I should invest some time in regex...it just keeps popping up everywhere...

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