Regular Expressions 101

Order By

Sponsors
There are currently no sponsors. Become a sponsor today!

Community Patterns

2

regex101: RFC1918 Private IPv4 Addresses, but limited to matching /24 subnet host IDs

PCRE2 (PHP >=7.3)
POSIX ERE compatible, suitable for usage in Bash [ testing Attributions Derived from [regex101: RFC1918 - Private IPv4 addresses by 0100101101001.
Submitted by anonymous - a year ago
2

Invalid Windows Filename Chars

PCRE (PHP <7.3)
https://docs.microsoft.com/en-us/windows/win32/fileio/naming-a-file Integer value zero, sometimes referred to as the ASCII NUL character. Characters whose integer representations are in the range from 1 through 31, except for alternate data streams where these characters are allowed. For more info...
Submitted by anonymous - a year ago (Last modified a year ago)
2

Check Email Validity

Java 8
Regular expression to check the email syntax validity. Certainly requires improvement, but it's a good basis to work from. Work with Java and JavaScript.
Submitted by Alain TOMASIAN <alain.tomasian@kaptus.fr> - a year ago (Last modified a year ago)
2

Quartz CRON Validation with groups

ECMAScript (JavaScript)
CRON validation Validates CRON pattern (Quartz) and supports groups. Useful for e.g. typescript or other typed languages. The following greoups are covered: second...
Submitted by Nico Vitt - 10 months ago
2

ROM naming scheme

PCRE2 (PHP >=7.3)
this is some cursed shit, but it does work. I use it to check whether all my ROMs have valid names or not. Makes it easier to read and, more importantly, deduplicate.
Submitted by Riedler - 7 months ago (Last modified 13 days ago)
2

RFC822 Date Format

PCRE2 (PHP >=7.3)
Test your RSS pubDate has a correctly formatted date value according to the RFC822 standard It will match timeZoneName (eg GMT, EST) or time zone offset (eg. +0100)
Submitted by anonymous - 6 months ago (Last modified 6 months ago)
2

Journalctl

PCRE2 (PHP >=7.3)
This was build on gentoo with english_ca.utf8 IIRC. Might not work for other distros... or locales supports -as the delimiter of hostname suffixing/prefixing
Submitted by Wolf1098 - 6 months ago
2

Parse Excel CSV data

PCRE2 (PHP >=7.3)
This is the best regex I found that was able to correctly parse cells containing multiple lines (hard line breaks). Low number of steps with sufficient speed, and it doesn't require /x option either. Source: https://gist.github.com/awwsmm/886ac0ce0cef517ad7092915f708175f
Submitted by thdoan - 6 months ago (Last modified 6 months ago)
2

unicode

PCRE2 (PHP >=7.3)
uncode word boundaries
Submitted by Mehmet Kozan - 6 months ago
2

Test 1 solution

PCRE2 (PHP >=7.3)
thanks
Submitted by Zeeble Dorp - 6 months ago
2

\tilde \alpha

PCRE2 (PHP >=7.3)
\tilde \alpha
Submitted by anonymous - 6 months ago
2

tst

PCRE2 (PHP >=7.3)
test
Submitted by anonymous - 5 months ago
2

Command line parser

.NET 7.0 (C#)
Supports parameters such as keys and values, also parameters enclosed in quotes.
Submitted by Pavel Bashkardin - 3 months ago (Last modified 3 months ago)
2

GitHub URL Parser

ECMAScript (JavaScript)
A regular expression for extracting the author, repository name, and optional branch from a GitHub repository or tree URL. Handles both HTTP(S) and direct GitHub links.
Submitted by Xain - 2 months ago
2

Quiz_1

PCRE2 (PHP >=7.3)
Check if a string contains the word word in it (case insensitive). If you have no idea, I guess you could try /word/.
Submitted by anonymous - 2 months ago
2

Quiz_17_Start_before_end

PCRE2 (PHP >=7.3)
Only match lines with the text start, unless text end appears prior to start. Note: end may or may not be in the string. Match start line_end; and don't match line_end; start
Submitted by anonymous - 2 months ago
2

Quiz_16_Repeated_Words

PCRE2 (PHP >=7.3)
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 - 2 months ago
2

Quiz_15_Not_surrounded_by_digits

PCRE2 (PHP >=7.3)
Replace every . (dot) with a - (hyphen) except when the dot is surrounded by digits. E.g.: .a.b.1.2. should become -a-b-1.2-
Submitted by anonymous - 2 months ago
2

Quiz_14_Spam_filter

PCRE2 (PHP >=7.3)
Match a string that contains any of the following substrings: http://, www., porn, or credit card. But don't match the text if it contains one of: not allowed, filter, or mirc. Don't use word boundaries (anywhere in the text is fine). If you need help, try reading this.
Submitted by anonymous - 2 months ago
2

Quiz_13_Match_Alternating_0s_And_1s_In_Any_Order

PCRE2 (PHP >=7.3)
I'm trying to match bit sequences which are alternating between 1 and 0 and never have more than one 1 or 0 in a row. They can be single digits. Try matching this: 0101010, 1010101010 or 1
Submitted by anonymous - 2 months ago
1...879880881882883...901

Community Library Entry

2

Regular Expression
PCRE2 (PHP >=7.3)

/
\b(?<!-)(?:\d{1,2}|100)\b
/
gmi
Open regex in editor

Description

Could you help me validate my input and only match positive integers between the range of 0 and 100?

There can be several numbers in a string which I would want to retrieve.

Try out these example strings:

Sam has 200 apples. He gives Todd 20 and Mary 125. The weather is -5 C today, but will be +5 C tomorrow.

Submitted by anonymous - 2 months ago