Regular Expressions 101

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/
[+-]?((\d+(\.\d*)?)|((\d*\.\d+)))(e[-+]?\d*)?
/
gm
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 the character + with index 4310 (2B16 or 538) literally (case sensitive)
- matches the character - with index 4510 (2D16 or 558) literally (case sensitive)
This hyphen is treated literally, which might be confusing for others. Consider escaping it or placing at the start or end of the class!
1st Capturing Group
((\d+(\.\d*)?)|((\d*\.\d+)))
1st Alternative
(\d+(\.\d*)?)
2nd Capturing Group
(\d+(\.\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)
\. matches the character . with index 4610 (2E16 or 568) literally (case sensitive)
\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)
2nd Alternative
((\d*\.\d+))
4th Capturing Group
((\d*\.\d+))
5th Capturing Group
(\d*\.\d+)
\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)
\. matches the character . with index 4610 (2E16 or 568) literally (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)
6th Capturing Group
(e[-+]?\d*)?
? matches the previous token between zero and one times, as many times as possible, giving back as needed (greedy)
e matches the character e with index 10110 (6516 or 1458) literally (case sensitive)
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 the character - with index 4510 (2D16 or 558) literally (case sensitive)
This hyphen is treated literally, which might be confusing for others. Consider escaping it or placing at the start or end of the class!
+ matches the character + with index 4310 (2B16 or 538) literally (case sensitive)
\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)
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