Regular Expressions 101

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/
(?<=\s)[+-]?\d+(?:.\d)?\d*
/
g
Positive Lookbehind
(?<=\s)
Assert that the Regex below matches
\s matches any whitespace character (equivalent to [\r\n\t\f\v ])
Match a single character present in the list below
[+-]
? matches the previous token between zero and one times, as many times as possible, giving back as needed (greedy)
+-
matches a single character in the list +- (case sensitive)
\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)
Non-capturing group
(?:.\d)?
? matches the previous token between zero and one times, as many times as possible, giving back as needed (greedy)
. matches any character (except for line terminators)
\d matches a digit (equivalent to [0-9])
\d
matches a digit (equivalent to [0-9])
* matches the previous token between zero and unlimited times, as many times as possible, giving back as needed (greedy)
Global pattern flags
g modifier: global. All matches (don't return after first match)
Your regular expression does not match the subject string.Try launching the debugger to find out why.

Regular Expression
No Match

/
/
g

Test String

Substitution

Processing...