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
"
(([0-9]){1,4})((\/))([0-9]){1,10}
"
1st Capturing Group
(([0-9]){1,4})
2nd Capturing Group
([0-9]){1,4}
{1,4} matches the previous token between 1 and 4 times, as many times as possible, giving back as needed (greedy)
A repeated capturing group will only capture the last iteration. Put a capturing group around the repeated group to capture all iterations or use a non-capturing group instead if you're not interested in the data
Match a single character present in the list below
[0-9]
0-9 matches a single character in the range between 0 (index 48) and 9 (index 57) (case sensitive)
3rd Capturing Group
((\/))
4th Capturing Group
(\/)
\/ matches the character / with index 4710 (2F16 or 578) literally (case sensitive)
5th Capturing Group
([0-9]){1,10}
{1,10} matches the previous token between 1 and 10 times, as many times as possible, giving back as needed (greedy)
A repeated capturing group will only capture the last iteration. Put a capturing group around the repeated group to capture all iterations or use a non-capturing group instead if you're not interested in the data
Match a single character present in the list below
[0-9]
0-9 matches a single character in the range between 0 (index 48) and 9 (index 57) (case sensitive)
Your regular expression does not match the subject string.

Regular Expression
No Match

r"
"

Test String