Regular Expressions 101

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Community Patterns

1

Quiz_2_Capitalizing_I

PCRE2 (PHP >=7.3)
Use substitution to replace every occurrence of the word i with the word I (uppercase, I as in me). E.g.: i'm replacing it. am i not? -> I'm replacing it. am I not?. A regex match is replaced with the text in the Substitution field when using substitution.
Submitted by anonymous - 2 months ago
1

Quiz_3_Uppercase_Consonants

PCRE2 (PHP >=7.3)
With regex you can count the number of matches. Can you make it return the number of uppercase consonants (B,C,D,F,..,X,Y,Z) in a given string? E.g.: it should return 3 with the text ABcDeFO!. Note: Only ASCII. We consider Y to be a consonant! Example: the regex /./g will return 3 when run against ...
Submitted by anonymous - 2 months ago
1

Quiz_4_Retrieve_Numbers

PCRE2 (PHP >=7.3)
Count the number of integers in a given string. Integers are, for example: 1, 2, 65, 2579, etc.
Submitted by anonymous - 2 months ago
1

Quiz_5_Whitespace

PCRE2 (PHP >=7.3)
Find all occurrences of 4 or more whitespace characters in a row throughout the string.
Submitted by anonymous - 2 months ago
1

Quiz_6_Broken_Keyboard

PCRE2 (PHP >=7.3)
Oh no! It seems my friends spilled beer all over my keyboard last night and my keys are super sticky now. Some of the time whennn I press a key, I get two duplicates. Can you ppplease help me fix thhhis? Substitute with $1
Submitted by anonymous - 2 months ago
1

Quiz_7_Validate_An_IP

PCRE2 (PHP >=7.3)
Validate an IPv4 address. The addresses are four numbered separated by three dots, and can only have a maximum value of 255 in either octet. Start by trying to validate 172.16.254.1.
Submitted by anonymous - 2 months ago
1

Quiz_8_HTML_Tags

PCRE2 (PHP >=7.3)
Strip all HTML tags from a string. HTML tags are enclosed in . The regex will be applied on a line-by-line basis, meaning partial tags will need to be handled by the regex. Don't worry about opening or closing tags; we just want to get rid of them all. Note: This task is meant to be a learning exe...
Submitted by anonymous - 2 months ago
1

Quiz_11_Validate_Floating_Point_Number

PCRE2 (PHP >=7.3)
Check if a floating point number (e.g. 3.14159) is in a valid format.
Submitted by anonymous - 2 months ago
1

Quiz_10_Followed_by_#

PCRE2 (PHP >=7.3)
For every occurrence of the char #, match the previous character and save it in a group (backreference). Example: for the text "a#bc# -#", set backreferences with a, c and -. You are not allowed to consume the hash character.
Submitted by anonymous - 2 months ago
1

Quiz_9_Match_An_Email

PCRE2 (PHP >=7.3)
Verify that a given e-mail address is valid. We all know how complex emails are, but despite this, let's give it a try and see what we can come up with. You could start by trying to match contact@regex101.com (denoted as @.).
Submitted by anonymous - 2 months ago
1

Test

PCRE2 (PHP >=7.3)
This is a test
Submitted by anonymous - 2 months ago
1

Validating IP V4

PCRE2 (PHP >=7.3)
VALIDATING IP V4 1.1.1.1 2.2.2.2 3.3.3.3 4.4.4.4 5.5.5.5...
Submitted by An0nym0us - 2 months ago
1

scam_18

PCRE2 (PHP >=7.3)
Replace every other character if it's a \d with * (only those in even positions: 2, 4, 6, etc). Example: a1b2cde3g45hi6 should become abcdeg4hi6
Submitted by anonymous - 2 months ago
1

scam_19

PCRE2 (PHP >=7.3)
Use substitution to put commas in all numbers to separate the thousands. ie: 12345678 → 12,345,678. The number could be in a sentence, and there may be more than one number in the sentence.
Submitted by anonymous - 2 months ago
1

scam_20

PCRE2 (PHP >=7.3)
Validate a line in quotes. Return one (and only one) backreference with the text. ie: quoted text from "quoted text". Note: a \ escapes any char, so \" is a valid escape.
Submitted by anonymous - 2 months ago
1

scam_4

PCRE2 (PHP >=7.3)
In an HTML page, replace the text micro with µ. Oh, and don't screw up the code: don't replace inside or &entities;
Submitted by anonymous - 2 months ago
1

PCRE2 (PHP >=7.3)

PCRE2 (PHP >=7.3)
Purpose: This is supposed to be a learning process. The first 1-9 tasks are supposed to be done with using "standard" regex, ie, teach the user to use \s, \w, \d, aswell as backrefs and similar basic things. Later down the road, at task 10-13 we start introducing them to lookarounds. These are fairl...
Submitted by An0nym0us - 2 months ago
1

Slash Separated Numbers

Golang
...
Submitted by Anonymous - 2 months ago
1

Fecha ISO 8601

PCRE2 (PHP >=7.3)
Validación para fechas en formato ISO 8601 como 2024-12-13
Submitted by Pablo - 2 months ago (Last modified 2 months ago)
1

Fecha formato europeo

PCRE2 (PHP >=7.3)
Validación de fecha de formato europeo 13/12/2024
Submitted by Pablo - 2 months ago
1...829830831832833...902

Community Library Entry

1

Regular Expression
PCRE2 (PHP >=7.3)

/
(?![AEIOU])[A-Z]
/
g
Open regex in editor

Description

With regex you can count the number of matches. Can you make it return the number of uppercase consonants (B,C,D,F,..,X,Y,Z) in a given string? E.g.: it should return 3 with the text ABcDeFO!. Note: Only ASCII. We consider Y to be a consonant!

Example: the regex /./g will return 3 when run against the string abc.

Submitted by anonymous - 2 months ago