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| author | Aaron Bedra and Stuart Halloway <pair@thinkrelevance.com> | 2009-08-23 15:01:31 -0400 |
|---|---|---|
| committer | Aaron Bedra and Stuart Halloway <pair@thinkrelevance.com> | 2009-08-23 15:01:31 -0400 |
| commit | b70cba0c656586836a3c951079012cd9d371fa40 (patch) | |
| tree | 5978f88adabee605391e817890fe337e95c39bc7 /src/clojure/contrib/seq_utils.clj | |
| parent | 0b8b47631efe950df74d17d8f410eb8196342359 (diff) | |
add seq-utils/positions
Diffstat (limited to 'src/clojure/contrib/seq_utils.clj')
| -rw-r--r-- | src/clojure/contrib/seq_utils.clj | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/src/clojure/contrib/seq_utils.clj b/src/clojure/contrib/seq_utils.clj index d4c29c46..5f3b7446 100644 --- a/src/clojure/contrib/seq_utils.clj +++ b/src/clojure/contrib/seq_utils.clj @@ -211,3 +211,21 @@ (cons (if (identical? x NIL) nil x) (drain)))))))))) +(defmulti positions + "Returns a lazy sequence containing the positions at which item + is found in coll. Functions (responding true to fn?) are called + against members of the collection, other items are compared for + equality." + { :arglists '([item-or-pred coll]) } + (fn [item-or-pred _] + (if (fn? item-or-pred) :pred :item))) + +(defmethod positions :pred [pred coll] + (for [[idx elt] (indexed coll) :when (pred elt)] idx)) + +(defmethod positions :item [item coll] + (for [[idx elt] (indexed coll) :when (= item elt)] idx)) + + + + |