Question

I’m pretty new to Emacs Lisp and still learning how to do some of the basics.

I have some text like [123] and I want to extract the number 123. I’ve goofed around with a few different attempts but I still can’t seem to capture the number reliably. The closest I’ve gotten is extracting the character ].

Can anyone point me in a direction? My biggest struggle is in understanding how to capture the number once I’ve used search-forwards and search-backwards to capture the point positions of the brackets.

Thanks in advance!

Answer 1

Try

(when (re-search-forward "\\[\\([0-9]+\\)\\]" nil t)
  (string-to-number (match-string 1)))

Alternatively, when the point is already on top of the number, thing-at-point may be more convenient:

(string-to-number (thing-at-point 'sexp))