I have a string logs as follow:
rgb(255, 255, 255) 0px 0px 0px 16px inset
I like to get the dynamic value, in the case above, 16. How do I write regex for the rule to match the last px then take out the digits between px and the space?
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Dylan Hsiao
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what have you tried so far? – Matt.G Jul 01 '18 at 00:47
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/\d\d(?=px)/ it does the work but not quite the rules above – Dylan Hsiao Jul 01 '18 at 00:48
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change `\d\d` to `\d+` in your regex – Matt.G Jul 01 '18 at 00:51
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that would match 0 0 0 16 – Dylan Hsiao Jul 01 '18 at 00:54
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will the string have `inset` at the end always? – Matt.G Jul 01 '18 at 00:55
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yeah, its a css property `box-shadow` – Dylan Hsiao Jul 01 '18 at 00:56
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1in that case try `\d+(?=px inset)` – Matt.G Jul 01 '18 at 00:59
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@Matt.G I'd say you should post that as a solution. – TheCrzyMan Jul 01 '18 at 01:04
1 Answers
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Since you say you just want the number before the last px, I won't assume that the text inset is always there. I would say \b\d+(?=px\b(?!.*\b\d+px\b)) is probably your safest bet.
blhsing
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2In case someone is interested I'll explain how this one works: `\b\d+` matches the begining of words that are digits, `(?=` is like an "and" operator as it checks if the following condition is also met, `px` checks if px is after the digit `(?!` is like a "not" operator as it checks if the following condition does not occur, and finally `\b\d+px\b` checks the same pattern as the beginning. In short it checks that the pattern "digit+px" exists and that after it, the same pattern does not occur again, so matches the last occurence. – Jul 01 '18 at 02:34
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1In case you want to test it, here it is in regex101. BTW, a very good site for creating and test your regexp's https://regex101.com/r/V11BVd/1 – Jul 01 '18 at 02:37
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1yeah I was using Regex101 to test. Thanks for all the detailed posted above! – Dylan Hsiao Jul 01 '18 at 04:39