Emacs: adding 1 to every number made of 2 digits inside a marked region

Question

Imagine I've got the following in a text file opened under Emacs:

some    34
word    30
another 38
thing   59
to      39
say     10
here    47

and I want to turn into this, adding 1 to every number made of 2 digits:

some    35
word    31
another 39
thing   60
to      40
say     11
here    48

(this is a short example, my actual need is on a much bigger list, not my call)

How can I do this from Emacs?

I don't mind calling some external Perl/sed/whatever magic as long as the call is made directly from Emacs and operates only on the marked region I want.

How would you automate this from Emacs?

I think the answer I'm thinking of consist in calling shell-command-on-region and replace the region by the output... But I'm not sure as to how to concretely do this.

Answer 1

Moderately tested; use M-: and issue the following command:

(while (re-search-forward "\\<[0-9][0-9]\\>" nil t) (let ((x (match-string 0))) (delete-backward-char 2) (insert (format "%d" (1+ (string-to-int x))))))

Answer 2

It doesn't protect against 99->100.

(defun add-1-to-2-digits (b e)
  "add 1 to every 2 digit number in the region"
  (interactive "r")
  (goto-char b)
  (while (re-search-forward "\\b[0-9][0-9]\\b" e t)
    (replace-match (number-to-string (+ 1 (string-to-int (match-string 0)))))))

Oh, and it operates on the region. If you want the entire file, then you replace b and e with (point-min) and nil.

Answer 3

This can be solved by using the command query-replace-regexp (bound to C-M-%):

C-M-% \b[0-9][0-9]\b return \,(1+ \#&)

The expression that follows \, would be evaluated as a Lisp expression, the result of which used as the replacement string. In the Lisp expression, \#& would be replaced by the matched string, interpreted as a number.

By default, this works on the whole document, starting from the cursor. To have this work on the region, there are several posibilities:

1. If transient-mark-mode is turned on, you just need to select the region normally (using point and mark);
2. If for some reason you don't like transient-mark-mode, you may use narrow-to-region to restrict the changes to a specific region: select a region using point and mark, C-x n n to narrow, perform query-replace-regexp as described above, and finally C-x n w to widen. (Thanks to Justin Smith for this hint.)
3. Use the mouse to select the region.

See section Regexp Replacement of the Emacs Manual for more details.

Answer 4

I managed to get it working in a different way using the following (my awk-fu ain't strong so it probably can be done in a simpler way):

C-u M-x shell-command-on-region RET awk '$2>=0&&$2<=99 {$2++} {print}' RET

but I lost my indentation in the process : )

Seeing all these answers, I can't help but have a lot of respect for Emacs...

Answer 5

Emacs' column editing mode is what you need.

• Activate it typing M-x cua-mode.

• Go to the beginning of the rectangle (leave cursor on character 3) and press C-RET.

• Go to the end of the rectangle (leave cursor on character 7). You will be operating on the highlighted region.

• Now press M-i which increments all values in the region.

You're done.