Regular Expressions 101

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Community Patterns

-2

Finds HTML img tags

PCRE (PHP <7.3)
no description available
Submitted by Matt Solum - 11 years ago
0

Verify and match e-mail address

PCRE (PHP <7.3)
no description available
Submitted by Josh K - 11 years ago
-1

Match the ID on individual Vimeo URLs

PCRE (PHP <7.3)
no description available
Submitted by Josh K - 11 years ago
1

.

PCRE (PHP <7.3)
no description available
Submitted by anonymous - 11 years ago
4

Get stuff inside <a> tags

PCRE (PHP <7.3)
Get stuff inside tags, which are between certain words
Submitted by Jerry - 11 years ago
1

Get inside single/double quotes

PCRE (PHP <7.3)
Get everything inside single/double quotes and ignoring escaped ones
Submitted by Jerry - 11 years ago
3

SQL select columns

PCRE (PHP <7.3)
no description available
Submitted by Phan - 11 years ago
-1

regex on paintkits

PCRE (PHP <7.3)
no description available
Submitted by anonymous - 11 years ago
2

Basic Phone Number Verification

PCRE (PHP <7.3)
Verifies a phone number
Submitted by anonymous - 11 years ago
1

Parse DateTimes

PCRE (PHP <7.3)
Will parse a DateTime and group the results. Probably pretty limited but it works for me.
Submitted by martin - 11 years ago
29

Wrap long string to spec length

PCRE (PHP <7.3)
no description available
Submitted by fullpipe - 11 years ago
4

Prime number regex

PCRE (PHP <7.3)
no description available
Submitted by originally "Abigail", comp.lang.perl.misc - 11 years ago
1

Twitter Hashtags

PCRE (PHP <7.3)
no description available
Submitted by anonymous - 11 years ago
-1

Twitter Hashtags

PCRE (PHP <7.3)
no description available
Submitted by anonymous - 11 years ago
3

Match quoted strings, ignoring escaped quotes

PCRE (PHP <7.3)
Matches single or double quoted strings, and ignores backslash-escaped quotes within the string.
Submitted by Maddingue - 12 years ago
6

Repair unquoted HTML attribute values

PCRE (PHP <7.3)
Usually MSWord HTML exports
Submitted by Ka. - 12 years ago
8

Validate Base64 single-line string

PCRE (PHP <7.3)
no description available
Submitted by ka. - 12 years ago
18

Date: DD-MM-YYYY hh:mm:ss

Recommended
PCRE (PHP <7.3)
Validate and capture dateTime parts, includes validation for leap years, range 1000-2999. Fixed bug
Submitted by Ka. - 12 years ago
0

DateTime: DD-MM-YYYY HH:mm:ss

PCRE (PHP <7.3)
Validate and Capture (in 1000-2999 range) Leap-Year Correct
Submitted by anonymous - 12 years ago
-18

dd-mm-YYYY HH:mm:ss (year range 1000-2999)

PCRE (PHP <7.3)
Validate Gregorian calendar dates that contain 24-hour times. This will also correctly match the Feb 29 date when it falls on a valid leap year. Leap years occur every 4 years, with one exception: when a year is evenly divisible by 100 but not evenly divisible by 400, the year will not be a leap ye...
Submitted by Ka. - 12 years ago (Last modified a year ago)
1...899900901902

Community Library Entry

2

Regular Expression
PCRE2 (PHP >=7.3)

/
(?=(\b\w{4,}\b)(?:.*\b\1\b){2})(?!(\b\w{4,}\b)(?:.*\b\1\b){3})
/
gi
Open regex in editor

Description

I'd like to know if a text contains words with 4 characters or more which are repeated 3 or more times in the text (anywhere in the text).

If so, set one (and only one) backreference for each word.

Submitted by anonymous - 3 months ago