Regular Expressions 101

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Community Patterns

27

Parsing browser User Agents

PCRE (PHP <7.3)
From a (fairly large) list of User Agent strings, extract the OS, Browser, and Device Type.
Submitted by OnlineCop - 10 years ago (Last modified a year ago)
33

Strict Password Validator

ECMAScript (JavaScript)
This regex matches only when all the following are true: password must contain 1 number (0-9) password must contain 1 uppercase letters password must contain 1 lowercase letters password must contain 1 non-alpha numeric number...
Submitted by qho - 7 years ago (Last modified a year ago)
13

CSS Color Matcher

ECMAScript (JavaScript)
Pattern matching and extracting color code formats using RegEx. https://github.com/Kyza/color-regex/
Submitted by Kyza - a year ago
30

Cron schedule

Recommended
PCRE (PHP <7.3)
Validate cron lines (even the ones commented out)
Submitted by anonymous - 8 years ago
20

best youtube id match ( iframe embed replace ready )

Recommended
PCRE (PHP <7.3)
MATCH ANY YOUTUBE ID author : mi-ca v1.0 – 2017.03.08 This Regex match any youtube url and grab the ID. Embed ready √ --...
Submitted by mi-ca.ch - 6 years ago
1...899900901

Community Library Entry

0

Regular Expression
PCRE (PHP <7.3)

/
(?<ipv6_full>(?:^(?:f[c-f][0-9a-f]{2}|200[1-2]|0?100):).+|(?:.+:0{0,3}1$|(?:.+:ffff:(?:0:)?|^0{0,2}64:ff9b::)(?<ipv4_map>(?:25[0-5]|2[0-4]\d|[0-1]?\d{1,2})(?:\.(?:25[0-5]|2[0-4]\d|[0-1]?\d{1,2})){3})$))
/
gm
Open regex in editor

Description

Detects whether a given IPv6 string is within a reserved block, as defined on https://en.wikipedia.org/wiki/IPv6_address#Special_addresses

Please note that this assume that the string given is already a valid IPv6 address - If IPv6 validation is important to you, please make sure you pass any string through a more general IPv6 validator before testing it against this regex.

Also allows for extracting mapped IPv4 addresses from the IPv4 mapped address ranges.

Submitted by Rohaq - 6 years ago