Count number of files with specific extension on a folder?

Question

Let's say I'd like to know how many .png images I have in a folder. In shell I'd run:

ls -1 | grep .png | wc -l

Is there a way to achieve this in emacs (preferably not just reading in from a shell output)?

After Phils' answer, some doc: wikemacs.org/wiki/Emacs_Lisp_Cheat_Sheet#File and github.com/rejeep/f.el, for the regexp wikemacs.org/wiki/Regexp — Ehvince, May 30 '16 at 10:37

phils · Accepted Answer · 2016-05-30 09:09:15Z

7

(length (directory-files "~/Pictures" nil "\\.png\\'"))

See C-hf directory-files

answered May 30 '16 at 9:09

phils

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Thanks. If I wanted to search for both .png and .jpeg, how would the regex look like? I tried [(.png)|(.jpeg)], but it matches other things too. – dangom May 30 '16 at 9:56
I'm afraid that wouldn't do what you wanted in any regular expression syntax I've ever seen. As per Ehvince's comment, you should definitely read some documentation. "\\.\\(png\\|jpeg\\)\\'" will do the trick in Emacs. – phils May 30 '16 at 10:53
Thanks. I'll go through the documentation. What I'd tried came from playing with the build-in re-builder – dangom May 30 '16 at 10:56
FYI you could also use the rx regexp compiler like so: (rx "." (or "png" "jpeg") string-end) – phils May 30 '16 at 10:59

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rchar01 · Accepted Answer · 2018-02-09 08:35:04Z

1

In dired (in directory in which you want to count .png files) run M-x eshell-command:

(length (directory-files "" nil "\\.png\\'"))

answered Feb 9 '18 at 8:35

rchar01

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