Regular Expressions 101

Order By

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

Community Patterns

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 days 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 days ago
2

Quiz_12_Match_Any_Number_Between_0-100

PCRE2 (PHP >=7.3)
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: ...
Submitted by anonymous - 2 days 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 days 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 days 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 days 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 days 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 days 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 days 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 days 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 days 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 days 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 days ago
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 days 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 days ago
1

Template Includes regex

PCRE2 (PHP >=7.3)
Part of the templates library i'm building
Submitted by anonymous - 2 days ago
1

Secure Apache WordPress Root Directory

PCRE2 (PHP >=7.3)
Secure Apache WordPress Root Directory using your Apache vhost config file instead of .htaccess by using this RegEx for file-name exclusions' i.e. (wp-activate|wp-mail|wp-signup) and {wp-} for all WordPress root files' starting with {wp-}. Excluding wp-activate.php, wp-signup.php and wp-mail.php fr...
Submitted by Scæntią - 4 days ago (Last modified 4 days ago)
1

Patentes chilenas con o sin guion

PCRE2 (PHP >=7.3)
AB-CD-12 AB-12-34 ABCD12 AB1234
Submitted by Pablo - 5 days ago
1

Patentes chilenas

PCRE2 (PHP >=7.3)
Validación de pantetes de automóviles en chile AB-CD-12 AB-12-34
Submitted by Pablo - 5 days ago
1

Direcciones

PCRE2 (PHP >=7.3)
Validación de direcciones en Chile
Submitted by Pablo - 5 days ago
1234...899

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 days ago