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
/
([#.a-z]{1}[a-z_]{1}[\s\S]+?){([\s\S]*?)}
/
g
1st Capturing Group
([#.a-z]{1}[a-z_]{1}[\s\S]+?)
Match a single character present in the list below
[#.a-z]
{1} matches the previous token exactly one time (meaningless quantifier)
#.
matches a single character in the list #. (case sensitive)
a-z matches a single character in the range between a (index 97) and z (index 122) (case sensitive)
Match a single character present in the list below
[a-z_]
{1} matches the previous token exactly one time (meaningless quantifier)
a-z matches a single character in the range between a (index 97) and z (index 122) (case sensitive)
_ matches the character _ with index 9510 (5F16 or 1378) literally (case sensitive)
Match a single character present in the list below
[\s\S]
+? matches the previous token between one and unlimited times, as few times as possible, expanding as needed (lazy)
\s matches any whitespace character (equivalent to [\r\n\t\f\v \u00a0\u1680\u2000-\u200a\u2028\u2029\u202f\u205f\u3000\ufeff])
\S matches any non-whitespace character (equivalent to [^\r\n\t\f\v \u00a0\u1680\u2000-\u200a\u2028\u2029\u202f\u205f\u3000\ufeff])
{ matches the character { with index 12310 (7B16 or 1738) literally (case sensitive)
2nd Capturing Group
([\s\S]*?)
Match a single character present in the list below
[\s\S]
*? matches the previous token between zero and unlimited times, as few times as possible, expanding as needed (lazy)
\s matches any whitespace character (equivalent to [\r\n\t\f\v \u00a0\u1680\u2000-\u200a\u2028\u2029\u202f\u205f\u3000\ufeff])
\S matches any non-whitespace character (equivalent to [^\r\n\t\f\v \u00a0\u1680\u2000-\u200a\u2028\u2029\u202f\u205f\u3000\ufeff])
} matches the character } with index 12510 (7D16 or 1758) literally (case sensitive)
Global pattern flags
g modifier: global. All matches (don't return after first match)
Your regular expression does not match the subject string.

Regular Expression
No Match

/
/
g

Test String

Substitution

Processing...