Regular Expressions 101

Save & Share

Flavor

  • PCRE2 (PHP >=7.3)
  • PCRE (PHP <7.3)
  • ECMAScript (JavaScript)
  • Python
  • Golang
  • Java 8

Function

  • Match
  • Substitution
  • List
  • Unit Tests
/
^([1-9]|[1-4]\d|50)$
/
^ asserts position at start of the string
1st Capturing Group
([1-9]|[1-4]\d|50)
1st Alternative
[1-9]
Match a single character present in the list below
[1-9]
1-9 matches a single character in the range between 1 (index 49) and 9 (index 57) (case sensitive)
2nd Alternative
[1-4]\d
Match a single character present in the list below
[1-4]
1-4 matches a single character in the range between 1 (index 49) and 4 (index 52) (case sensitive)
\d matches a digit (equivalent to [0-9])
3rd Alternative
50
50
matches the characters 50 literally (case sensitive)
$ asserts position at the end of the string
Your regular expression does not match the subject string.

Regular Expression
No Match

/
/

Test String