Regular Expressions 101

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  • Unit Tests (8)
`
^func (\(.*\) )?[a-zA-Z0-9]+?\((.*?)\) [a-zA-Z0-9 ]*?\{
`
gm
^ asserts position at start of a line
func
matches the characters func literally (case sensitive)
1st Capturing Group
(\(.*\) )?
? matches the previous token between zero and one times, as many times as possible, giving back as needed (greedy)
\( matches the character ( with index 4010 (2816 or 508) literally (case sensitive)
.
matches any character (except for line terminators)
* matches the previous token between zero and unlimited times, as many times as possible, giving back as needed (greedy)
\) matches the character ) with index 4110 (2916 or 518) literally (case sensitive)
matches the character with index 3210 (2016 or 408) literally (case sensitive)
Match a single character present in the list below
[a-zA-Z0-9]
+? matches the previous token between one and unlimited times, as few times as possible, expanding as needed (lazy)
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)
0-9 matches a single character in the range between 0 (index 48) and 9 (index 57) (case sensitive)
\( matches the character ( with index 4010 (2816 or 508) literally (case sensitive)
2nd Capturing Group
(.*?)
.
matches any character (except for line terminators)
*? matches the previous token between zero and unlimited times, as few times as possible, expanding as needed (lazy)
\) matches the character ) with index 4110 (2916 or 518) literally (case sensitive)
matches the character with index 3210 (2016 or 408) literally (case sensitive)
Match a single character present in the list below
[a-zA-Z0-9 ]
*? matches the previous token between zero and unlimited times, as few times as possible, expanding as needed (lazy)
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)
0-9 matches a single character in the range between 0 (index 48) and 9 (index 57) (case sensitive)
matches the character with index 3210 (2016 or 408) literally (case sensitive)
\{ matches the character { with index 12310 (7B16 or 1738) literally (case sensitive)
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.

Regular Expression
No Match

`
`
gm

Test String