Regular Expressions 101

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/
(^\d{2})(\d{7}$|\d{9}$)
/
1st Capturing Group
(^\d{2})
^ asserts position at start of the string
\d
matches a digit (equivalent to [0-9])
{2} matches the previous token exactly 2 times
2nd Capturing Group
(\d{7}$|\d{9}$)
1st Alternative
\d{7}$
\d
matches a digit (equivalent to [0-9])
{7} matches the previous token exactly 7 times
$ asserts position at the end of the string, or before the line terminator right at the end of the string (if any)
2nd Alternative
\d{9}$
\d
matches a digit (equivalent to [0-9])
{9} matches the previous token exactly 9 times
$ asserts position at the end of the string, or before the line terminator right at the end of the string (if any)
Your regular expression does not match the subject string.Try launching the debugger to find out why.

Regular Expression
No Match

/
/

Test String