Backreferences

/(?:(\d*)\s*)+/

• Here's a FAQ:

• If you try to match 12 34 56, only the 56 goes into $1.

• Why? Isn't the + supposed to `repeat'?

• What does it do?

  • Start copying, copy the 12 into $1, stop copying, repeat

  • Start copying, copy the 34 into $1, stop copying, repeat

  • Start copying, copy the 56 into $1, stop copying, end of string

• End result: Only 56 is in $1.

• Solutions:

  • Use split

  • Use m//g (coming up)

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Copyright © 2002 M. J. Dominus