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 (13)
"
D([0-2]?[0-9a-zA-Z]?)$
"
D matches the character D with index 6810 (4416 or 1048) literally (case sensitive)
1st Capturing Group
([0-2]?[0-9a-zA-Z]?)
Match a single character present in the list below
[0-2]
? matches the previous token between zero and one times, as many times as possible, giving back as needed (greedy)
0-2 matches a single character in the range between 0 (index 48) and 2 (index 50) (case sensitive)
Match a single character present in the list below
[0-9a-zA-Z]
? matches the previous token between zero and one times, as many times as possible, giving back as needed (greedy)
0-9 matches a single character in the range between 0 (index 48) and 9 (index 57) (case sensitive)
a-z matches a single character in the range between a (index 97) and z (index 122) (case sensitive)
A-Z matches a single character in the range between A (index 65) and Z (index 90) (case sensitive)
$ asserts position at the end of the string, or before the line terminator right at the end of the string (if any)

Regular Expression

r"
"

Unit Tests

Unspecified unit test
Unspecified unit test
Unspecified unit test
Unspecified unit test
Unspecified unit test
Unspecified unit test
Unspecified unit test
Unspecified unit test
Unspecified unit test
Unspecified unit test
Unspecified unit test
Unspecified unit test
Unspecified unit test