Function: -intersection

-intersection is a byte-compiled function defined in dash.el.

Signature

(-intersection LIST1 LIST2)

Documentation

Return a new list of distinct elements appearing in both LIST1 and LIST2.

The test for equality is done with equal, or with -compare-fn if that is non-nil.

View in manual

Source Code

;; Defined in ~/.emacs.d/elpa/dash-20260221.1346/dash.el
(defun -intersection (list1 list2)
  "Return a new list of distinct elements appearing in both LIST1 and LIST2.

The test for equality is done with `equal', or with `-compare-fn'
if that is non-nil."
  (declare (important-return-value t))
  (let (test len)
    (cond ((null (and list1 list2)) ())
          ;; Use a hash table if `-compare-fn' is a known hash table
          ;; test function and either list is long enough.
          ((and (setq test (dash--hash-test-fn))
                (> (setq len (length list2)) dash--short-list-length))
           (let ((ht (make-hash-table :test test :size len)))
             (--each list2 (puthash it t ht))
             ;; Remove visited elements to avoid duplicates.
             (--filter (when (gethash it ht) (remhash it ht) t) list1)))
          ((let ((member (dash--member-fn)) intersection)
             (--each list1 (and (funcall member it list2)
                                (not (funcall member it intersection))
                                (push it intersection)))
             (nreverse intersection))))))