What are regular expression patterns?
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Comprehensive Model Answer
Verified Solution
Regular Expressions provide a group of patterns in order to match characters. Basically they are categorized into 3 types,
- 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 |
- 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
- 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
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