Distinguishing files with extensions, from hidden files and no extensions

Question

I\'m having difficulty distinguishing files with extensions, from files without extensions, and hidden files. I\'m using (file-name-extens

Answer 1

How about

(let* ((input-regexp '("odt" "wpd" "docx" "doc" "xls" "pdf" "tif" "bmp" "jpg"))
       (input-filename (dired-get-file-for-visit))
       (ext (file-name-extension input-filename)))
  (unless (and ext (regexp-match-p input-regexp ext))
    (find-file input-filename)))

Alternatively, redefine

(defun regexp-match-p (regexps string)
  (and string
       (catch 'matched
         (let ((inhibit-changing-match-data t)) ; small optimization
           (dolist (regexp regexps)
             (when (string-match regexp string)
               (throw 'matched t)))))))