Regular Expressions 101

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Library entries

102
javascript

trim

trim string
Submitted by fp - 9 years ago
36
pcre

http://

no description available
Submitted by Mitus M. - 9 years ago
35
javascript

IP Address validator

Validates IPv4 IP Address
Submitted by krzysp - 7 years ago
31
pcre

ninite

no description available
Submitted by peek - 7 years ago
30
javascript

Email address (most used)

Email address, most used cases
Submitted by Jago - 7 years ago
27
pcre

Wrap long string to spec length

no description available
Submitted by fullpipe - 9 years ago
23
pcre

userName

1-15 alphanumeric login name
Submitted by gsanchezc - 7 years ago

match valid JSON

Vote

26

Regular Expression
pcre

/
(?(DEFINE) # Note that everything is atomic, JSON does not need backtracking if it's valid # and this prevents catastrophic backtracking (?<json>(?>\s*(?&object)\s*|\s*(?&array)\s*)) (?<object>(?>\{\s*(?>(?&pair)(?>\s*,\s*(?&pair))*)?\s*\})) (?<pair>(?>(?&STRING)\s*:\s*(?&value))) (?<array>(?>\[\s*(?>(?&value)(?>\s*,\s*(?&value))*)?\s*\])) (?<value>(?>true|false|null|(?&STRING)|(?&NUMBER)|(?&object)|(?&array))) (?<STRING>(?>"(?>\\(?>["\\\/bfnrt]|u[a-fA-F0-9]{4})|[^"\\\0-\x1F\x7F]+)*")) (?<NUMBER>(?>-?(?>0|[1-9][0-9]*)(?>\.[0-9]+)?(?>[eE][+-]?[0-9]+)?)) ) \A(?&json)\z
/
x

Description

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Submitted by Mateon1 - 8 years ago