Difference between revisions of "Regexp"
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/[A-Z]:[0-3]\.\S{1,8}/ | /[A-Z]:[0-3]\.\S{1,8}/ | ||
describes a pattern that will match, for example, the strings ''B:1.HelloSir'' or '''A:0.Good''. But it will not match ''a:2.darn'' because the first letter must be uppercase. | describes a pattern that will match, for example, the strings ''B:1.HelloSir'' or '''A:0.Good''. But it will not match ''a:2.darn'' because the first letter must be uppercase. | ||
| + | |||
| + | Bounding a whole word: | ||
| + | /\bWord\b/ | ||
==See also== | ==See also== | ||
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*[[Sed]] | *[[Sed]] | ||
*[[Awk]] | *[[Awk]] | ||
| + | *[[Tr]] | ||
*[[Python]] | *[[Python]] | ||
*[[Ruby]] | *[[Ruby]] | ||
Latest revision as of 21:54, 3 November 2010
Regexp stands for regular expressions. Regular expressions are what made languages like Awk and Perl notorious. Regular expressions are expressions equating a pattern string. To write a regular expression in Perl on must insert it between slashes (/regexp/)For example:
/[a-z]/
means all the alphabet lowercase letters.
/[0-4]/
stands for all the digits from 0 to 4 inclusive.
/\d{2,5,7}/
stands for all the sequences of 2, 5 or 7 digits.
The interesting thing is that you can compose regexps into complex patterns. For example the regexp
/[A-Z]:[0-3]\.\S{1,8}/
describes a pattern that will match, for example, the strings B:1.HelloSir or 'A:0.Good. But it will not match a:2.darn because the first letter must be uppercase.
Bounding a whole word:
/\bWord\b/
