RegEx: Match format around text;

Question

I have an instance in a project where I need to match some text within a description or title;

The requirements for matching are as follows;

Should Match:

a) Any occurrences of "Volume" OR "Part" (Case Insensitive);

b) Any occurrence of "vol" or "pt" (CI) that does not have [[comma][space] before AND [period] after;

I have tried numerous different regex patterns (count down from the 4) on regex101 here: http://regex101.com/r/lO9vO9/4

In that link, theres a few lines that fail, that I would like to, ideally, match.

. pt. as it contains the pt with trailing period, but has the wrong character (period) before it when expecting a comma

The Red Pill, Pt 2 As it contains the preceding comma and the PT, but misses the period after PT.

If someone can help me with this, I would appreciate it if a run down of how it works was available too - so I can figure out where I went wrong.

score 2 · Accepted Answer · edited May 23 '17 at 12:06

2

You can use this regex:

(,\s(?:vol|pt)\.(*SKIP)(*F)|\b(?:volume|pt|vol|part)\b)

RegEx Demo

This part ,\s(?:vol|pt)\. just matches your negative pattern and (*SKIP)(*F) just skips it from final match.

More info on (*SKIP) and (*FAIL)

edited May 23 '17 at 12:06

Community

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answered Nov 26 '14 at 17:14

anubhava

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"volume" should come before "vol" in the last part, otherwise "volume" won't be found. (*SKIP) and (*F) are new to me. Where can I get info on them? – Pedro Gimeno Nov 26 '14 at 19:19
Ok that regex is updated, **[see this Q&A for more info on these features](http://stackoverflow.com/questions/19992984/verbs-that-act-after-backtracking-and-failure)** – anubhava Nov 26 '14 at 19:39

Casimir et Hippolyte · Answer 2 · 2014-11-26T19:27:29.360

So, in other words you want to forbid, pt & vol not followed by a dot, and pt & vol not preceded by a comma and a space:

volume|part|(?<!, )(?:vol|pt)|(?:vol|pt)(?!\.)

demo

Note: you can improve this pattern by adding a lookahead and word boundary at the begining (in this way, the alternation is only tested for words that begin with p and v). You can check too that "vol" or "pt" is not the begining of another word by forcing that no letters follow.

(?=\b[pv])(?:volume|part|(?<!, )(?:vol|pt)|(?:vol|pt)(?!\.))(?![a-z])

RegEx: Match format around text;

Should Match:

2 Answers2

RegEx Demo