Regular Expressions 101

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"
\(*(\d{3})(?:(?:-*|\s*|\.*|\)*|\)\s*))(\d{3})(?:(?:-*|\s*|\.*|\)*))(\d{4})
"
g
\(
matches the character ( with index 4010 (2816 or 508) literally (case sensitive)
* matches the previous token between zero and unlimited times, as many times as possible, giving back as needed (greedy)
1st Capturing Group
(\d{3})
\d
matches a digit (equivalent to [0-9])
{3} matches the previous token exactly 3 times
Non-capturing group
(?:(?:-*|\s*|\.*|\)*|\)\s*))
Non-capturing group
(?:-*|\s*|\.*|\)*|\)\s*)
1st Alternative
-*
-
matches the character - with index 4510 (2D16 or 558) literally (case sensitive)
2nd Alternative
\s*
\s
matches any whitespace character (equivalent to [\r\n\t\f\v  ])
* matches the previous token between zero and unlimited times, as many times as possible, giving back as needed (greedy)
3rd Alternative
\.*
\.
matches the character . with index 4610 (2E16 or 568) literally (case sensitive)
* matches the previous token between zero and unlimited times, as many times as possible, giving back as needed (greedy)
4th Alternative
\)*
\)
matches the character ) with index 4110 (2916 or 518) literally (case sensitive)
* matches the previous token between zero and unlimited times, as many times as possible, giving back as needed (greedy)
5th Alternative
\)\s*
\) matches the character ) with index 4110 (2916 or 518) literally (case sensitive)
\s
matches any whitespace character (equivalent to [\r\n\t\f\v  ])
* matches the previous token between zero and unlimited times, as many times as possible, giving back as needed (greedy)
2nd Capturing Group
(\d{3})
\d
matches a digit (equivalent to [0-9])
{3} matches the previous token exactly 3 times
Non-capturing group
(?:(?:-*|\s*|\.*|\)*))
Non-capturing group
(?:-*|\s*|\.*|\)*)
1st Alternative
-*
-
matches the character - with index 4510 (2D16 or 558) literally (case sensitive)
2nd Alternative
\s*
\s
matches any whitespace character (equivalent to [\r\n\t\f\v  ])
* matches the previous token between zero and unlimited times, as many times as possible, giving back as needed (greedy)
3rd Alternative
\.*
\.
matches the character . with index 4610 (2E16 or 568) literally (case sensitive)
* matches the previous token between zero and unlimited times, as many times as possible, giving back as needed (greedy)
4th Alternative
\)*
\)
matches the character ) with index 4110 (2916 or 518) literally (case sensitive)
* matches the previous token between zero and unlimited times, as many times as possible, giving back as needed (greedy)
3rd Capturing Group
(\d{4})
\d
matches a digit (equivalent to [0-9])
{4} matches the previous token exactly 4 times
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

r"
"
g

Test String