Regular Expressions Syntax

We know that regular expressions are used for pattern matching. Let’s look at how to write and understand a RegEx.

Syntax

A regular expression can find a matching substring or test if a string passes a certain criterion. Let’s look at the syntax of RegEx.

Brackets

Brackets, or square brackets [], are patterns that find a range of characters in the string. The brackets encapsulate the criteria or pattern that the string needs to satisfy. This chart shows how brackets are used.

Expression	Description
[...]	Any of the characters encapsulated in the brackets with ... representing any character or pattern.
[^...]	Not any character encapsulated in the brackets where ... represents any character or pattern. The ^ represents Not.
[0-9]	Any number between 0 and 9
[a-z]	Any character from lowercase letter ‘a’ to lowercase letter ‘z’

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