How do EMACS Lisp programmers read text files for non-editing purposes? -

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what emacs lisp programmers do, when want write equivalent of...

for line in open("foo.txt", "r", encoding="utf-8").readlines():     ...(split on ws , call fn, or whatever)...

..?

when in emacs lisp help, see functions opening files text editing buffers -- not intending. suppose write functions visit lines of file, if did that, wouldn't want user see it, , besides, doesn't seem efficient text-processing standpoint.

i think more direct translation of original python code follows:

(with-temp-buffer   (insert-file-contents "foo.txt")   (while (search-forward-regexp "\\(.*\\)\n?" nil t)     ; line in (match-string 1)     ))

i think with-temp-buffer/insert-file-contents preferable with-current-buffer/find-file-noselect, because former guarantees you're working fresh copy of entire file contents. latter construction, if happen have buffer visiting target file, buffer returned find-file-noselect, if buffer has been narrowed, you'll see part of file when process it.

keep in mind may more convenient not process file line-by-line. example, expression returns list of sequences of consecutive digits in file:

(with-temp-buffer   (insert-file-contents "foo.txt")   (loop while (search-forward-regexp "[0-9]+" nil t)         collect (match-string 0)))

(require 'cl) first bring in loop macro.


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