What are regular expression patterns
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Regular Expressions provide a group of patterns in order to match characters. Basically they are categorized into 3 types,
1. Brackets: These are used to find a range of characters. For example, below are some use cases,
[abc]: Used to find any of the characters between the brackets(a,b,c)
[0-9]: Used to find any of the digits between the brackets
(a|b): Used to find any of the alternatives separated with |
2. Metacharacters: These are characters with a special meaning. For example, below are some use cases,
\d: Used to find a digit
\s: Used to find a whitespace character
\b: Used to find a match at the beginning or ending of a word
3. Quantifiers: These are useful to define quantities. For example, below are some use cases,
n+: Used to find matches for any string that contains at least one n
n*: Used to find matches for any string that contains zero or more occurrences of n
n?: Used to find matches for any string that contains zero or one occurrences of n