Regular Expressions 101

Save & Share

  • Save Regex
    ctrl+s
  • Update Regex
    ctrl+⇧+s

Flavor

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

Function

  • Match
  • Substitution
  • List
  • Unit Tests
/
^(?:\d{8}[A-Z]|\d{1,8})$
/
gm
^ asserts position at start of a line
Non-capturing group
(?:\d{8}[A-Z]|\d{1,8})
1st Alternative
\d{8}[A-Z]
\d
matches a digit (equivalent to [0-9])
{8} matches the previous token exactly 8 times
Match a single character present in the list below
[A-Z]
A-Z matches a single character in the range between A (index 65) and Z (index 90) (case sensitive)
2nd Alternative
\d{1,8}
\d
matches a digit (equivalent to [0-9])
{1,8} matches the previous token between 1 and 8 times, as many times as possible, giving back as needed (greedy)
$ asserts position at the end of a line
Global pattern flags
g modifier: global. All matches (don't return after first match)
m modifier: multi line. Causes ^ and $ to match the begin/end of each line (not only begin/end of string)
Your regular expression does not match the subject string.Try launching the debugger to find out why.

Regular Expression
No Match

/
/
gm

Test String