Regular Expression

Regular expressions(RegEx) are an extremely powerful tool for manipulating text and data. They are now standard features in a wide range of languages and popular tools, including perl, python, ruby, grep, awk and so on.

Every languages or tools didn't support the standard RegEx. Just implemented with a subset by the own purpose. Enough to use is OK, Perfect is not perfect. RegEx can save my time and aggravation. Once I’ve mastered RegEx, They’ll become an invaluable part of my toolkit.

 

Metacharacters

Wildcard*

^(caret) and $(dollar), which represent the START and END.

[…] match any one of several characters

[^…] negated character classes

. match any character with DOT

| match any one of several subexpressions

/< /> word boundaries

? optional item

+ one or more of the immediately-preceding item

{min, max} defined range of matches