[RESOLVED] RegEx help

Good2CU

I want to have a regular expression that would match any string (consisting of one or more words) that contains words which are not in a list of specified words in the RegEx.

For example "cool regular expression" would be returned but "regular expression" would not, assuming the RegEx is something like:
\b[^{(regular|expression)]\b}

I've tried just about every possible combo I can think of and can't get it to work.

If it's not possible, I could use something similar that would require all individual words within a string each individually match the list of specified words.

bradgrafelman

One technique might be to use [man]preg_replace/man to strip out all of the words in the given list, then use a [man]preg_match/man on that new (temporary?) string to see if any "words" are left.

Good2CU

In this case I'm using the regex within Google Analytics, so I'm guessing that's not something they support.

johanafm

Good2CU;11032785 wrote:
I want to have a regular expression that would match any string (consisting of one or more words) that contains words which are not in a list of specified words

So if any of the words in that list match, it's a failure?

if (!preg_match('#word1|word2|...|wordn#'))

Good2CU

johanafm;11032815 wrote:
So if any of the words in that list match, it's a failure?

No, if any words don't match it's a success. I'm not great at logic, but I think this is some kind of And vs. Or thing, either way, I'm pretty sure the double-negative of what I'm saying isn't necessarily true, at least if you're putting "any" in front of both statements.

If you could change your statement to "if ALL of the words in the string match any of words specified in the regex, it's a failure" that would be fine (but it can't be ALL words in the string match ALL words in the regex)

I want to say return everything that doesn't contain "this" or "this2" or "this3", so "this and that" would be returned but "this this2" would be excluded

I will provide a list of white-listed words and anything that shows up with a word that is not in that white-list should be returned so it can be reviewed.

I have something working that returns all keywords where the non-white-list word(s) come before a white-listed word, which is partially correct and still useful, but as soon as it finds a white listed word, it stops checking and excludes it.

Thanks for the help!

johanafm

Googel analytics - I have no idea what they can and cannot do, or in what way you provide the regular expression. This one is without pattern delimiters and lacks options.

((?<!$words)\W)|(\W(?!$words))

This regexp matches when either
1. Anything not in the word list is followed by a non-word character
or
2. When a non-word character is followed by anything not in the word list.

Do note that "anything not in the word list" doesn't mean any word not in the word list. Thus, the above will match two consecutive non-word characters, such as full stop followed by whitespace: ". "
Since I don't know on what kind of strings you operate, I have no idea if this is good enough or if you for example would get one "faulty match" per sentence.

Good2CU

Unfortunately Google Analytics doesn't support lookaheads/behinds and other advanced features.

I ended up modifying the regex I had working that filtered when the first word was not in the list to have a separate one for the last word and then another for 2nd, 3rd etc. I end up having to run 8 different rules, but I'm pretty sure it's the only way for Google Analytics after doing a lot research on it.

Thanks for your help!