How show (filter) only text lines with all uppercase chars?

Question

Suppose I has the next text:

test
HELLO
help
HOW ARE YOU
buy

I need to get (filter) only text lines with all uppercase chars. So result must be like this:

HELLO
HOW ARE YOU

Your result contains newline and space which are not uppercase chars. — xuchunyang, Dec 30 '18 at 13:33
ok, with all uppercase, spaces and newline. How I can do this? — a_subscriber, Dec 30 '18 at 15:23
Does this answer your question? [how do I quickly remove lines from emacs buffer](https://emacs.stackexchange.com/questions/40596/how-do-i-quickly-remove-lines-from-emacs-buffer) — Drew, Sep 23 '21 at 22:55
@Drew This help https://emacs.stackexchange.com/questions/68641/keep-lines-only-upper-case-not-working/68648#68648 — a_subscriber, Sep 24 '21 at 09:39

score 2 · Answer 1 · answered Dec 31 '18 at 12:35

2

There are two very useful interactive built-in functions flush-lines and keep-lines that take a regular expression as an argument that modify the current buffer.

Place the cursor before the lines you want to filter and run M-x keep-lines with argument ^[A-Z ]+$ to get the result you want.

answered Dec 31 '18 at 12:35

Heikki

2,961
11
18

This answer is better. Any idea why does `M-x flush-lines` with argument `[^A-Z ]` and `[^A-Z \n]` also flush the lines of uppercase letters and spaces? Am I missing something? My Emacs version is 26.1. – whatacold Dec 31 '18 at 15:24

score 1 · Accepted Answer · answered Dec 30 '18 at 15:58

Do you want this? only-uppercase is used to test which item should be remove(t:leave, nil: remove). Then seq-filter to filter the input items.

(defun only-uppercase (str)
  "only uppercase"
  (if (numberp
       (let ((case-fold-search nil))
     (string-match-p "[a-z]" str)))
      nil t))

(defun filter-uppercase ()
  "filter uppercase"
  (interactive)
  (print
  (seq-filter
   'only-uppercase
    (split-string
    (buffer-substring-no-properties (region-beginning) (region-end))
    "\n" t))))

How show (filter) only text lines with all uppercase chars?

2 Answers2

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