Regular Expression is a
What Is Regular Expression ?
Regular Expression (RegExp) a sequence of symbols and characters expressing a string or pattern to be searched for within a longer piece of text. Read More
What can a regular expression be used for ?
A regular expression can be a single character, or a more complicated pattern. Regular expressions can be used to perform all types of text search and text replace operations. /w3schools/i is a regular expression.
Which is the best example of a regex ?
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Anchors — ^ and $
RegExp Explanations ^Hello matches any string that starts with Hello -> Try it! world$ matches a string that ends with world ^Hello world$ exact string match (starts and ends with Hello world) Hello matches any string that has the text Hello in it -
Quantifiers — * + ? and {}
RegExp Explanations abc* matches a string that has ab followed by zero or more c -> Try it! abc+ matches a string that has ab followed by one or more abc? matches a string that has ab followed by zero or one abc{2} matches a string that has ab followed by 2 abc{2,} matches a string that has ab followed by 2 or more abc{2,5} matches a string that has ab followed by 2 up to 5 ca(bc)* matches a string that has a followed by zero or more copies of the sequence bca(bc){2,5} matches a string that has a followed by 2 up to 5 copies of the sequence bc -
OR operator — | or []
RegExp Explanations a(b|c) matches a string that has a followed by b or c (and captures b or c) -> Try it! a[bc] same as previous, but without capturing b or c -
Character classes — \d \w \s and .
RegExp Explanations