Regular Expressions 101

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/
^(\-{0,1})(?:(?:0*)(\d+))?((?:\.)(?:\d*?))?0*$
/
gm
^ asserts position at start of a line
1st Capturing Group
(\-{0,1})
\-
matches the character - with index 4510 (2D16 or 558) literally (case sensitive)
{0,1} matches the previous token between zero and one times, as many times as possible, giving back as needed (greedy)
Non-capturing group
(?:(?:0*)(\d+))?
? matches the previous token between zero and one times, as many times as possible, giving back as needed (greedy)
Non-capturing group
(?:0*)
0
matches the character 0 with index 4810 (3016 or 608) literally (case sensitive)
2nd Capturing Group
(\d+)
\d
matches a digit (equivalent to [0-9])
+ matches the previous token between one and unlimited times, as many times as possible, giving back as needed (greedy)
3rd Capturing Group
((?:\.)(?:\d*?))?
? matches the previous token between zero and one times, as many times as possible, giving back as needed (greedy)
Non-capturing group
(?:\.)
\. matches the character . with index 4610 (2E16 or 568) literally (case sensitive)
Non-capturing group
(?:\d*?)
\d
matches a digit (equivalent to [0-9])
*? matches the previous token between zero and unlimited times, as few times as possible, expanding as needed (lazy)
0
matches the character 0 with index 4810 (3016 or 608) literally (case sensitive)
$ 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

Substitution

Processing...