Character Classes

Code

[abc]      any of a, b, c
[^abc]     none of a, b, c
[a-z]      range a to z
[A-Z0-9]   uppercase letter or digit
\d         digit          [0-9]
\D         non-digit
\w         word char      [A-Za-z0-9_]
\W         non-word char
\s         whitespace
\S         non-whitespace
.          any char except newline

Explanation

Character classes match a single character from a set, with ranges like a-z and negation via a leading caret. Shorthand escapes such as \d, \w, and \s are built-in classes for digits, word characters, and whitespace, with uppercase variants meaning their complement. The dot matches any character except a newline unless the dotall flag is set.

More Regex Snippets