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| author | William Carroll <wpcarro@gmail.com> | 2020-02-14T15·34+0000 |
|---|---|---|
| committer | William Carroll <wpcarro@gmail.com> | 2020-02-14T15·34+0000 |
| commit | fa779ab7bfd7bd0b9decaf2501265dbf2e28930b (patch) | |
| tree | bfd873b96e062d9f1e2d0c6712ed843ef0f1869b | |
| parent | 3677a7a39e47bd9d295ae63e3a40e6cf98947506 (diff) | |
Support list/xs-distinct-by?
Supporting a predicate to check that all elements in a list are distinct after applying a transformation function to them.
| -rw-r--r-- | emacs/.emacs.d/wpc/list.el | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/emacs/.emacs.d/wpc/list.el b/emacs/.emacs.d/wpc/list.el index 5a63c8bd94e0..83c4c5ccdc42 100644 --- a/emacs/.emacs.d/wpc/list.el +++ b/emacs/.emacs.d/wpc/list.el @@ -199,6 +199,11 @@ Be leery of using this with things like alists. Many data structures in Elisp "Return t if X is in XS using `equal'." (-contains? xs x)) +(defun list/xs-distinct-by? (f xs) + "Return t if all elements in XS are distinct after applying F to each." + (= (length xs) + (->> xs (-map f) set/from-list set/count))) + ;; TODO: Support dedupe. ;; TODO: Should we call this unique? Or distinct? |