I have the following valid regex to match various excel cell/range patterns, of the form A1, A1:Z12, etc.

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  And a better approach would be to use ?1 to recurse to the first pattern:

  • ^([A-Z]{1,3}[0-9]{1,10})(:(?1))?$

  Note however with this approach we do need the extraneous capturing group at the beginning for this technique to work.