A long time ago, I took a look at using boundary , studying about regular expressions in PHP (PCRE Patterns).
I came across the \b (which is called boundary).
How useful is it in a regular expression?
What is a boundary (b) in a regular expression?
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asked by anonymous 30.01.2016 / 20:12
1 answer
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The \b (beta) is an anchor as well as its ^ (alpha) and $ (omega) primes. Once added on one side of the regex will capture pattern specified at the beginning, end or exact , that means that it is valid only for letters, numbers and the underline (% with_%) which is the equivalent to [A-Za-z0-9_] .
Entry:
dialogo dia melodia diafragma dialeto radial bom-dia
Collapse at the beginning \w capture strings that contain at the beginning (not the beginning of the line ) the default \bdia , the items that enter the capture are, day logo, day , day fragma, strong> leto and bom- day
Anchor at the end dia captures strings (words) where the specified pattern is at the end, the captured items are: day , day and day
Extent anchor dia\b captures strings day and good - day
References
30.01.2016 / 21:33