performance - SCALA: Which data structures are optimal in which siutations when using ".contains()" or ".exists()"? -

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i know in situations data structures optimal using "contains" or "exists" checks.

i ask because come python background , used using if x in something: expressions everything. example, expressions evaluated quickest:

val m = map(1 -> 1, 2 -> 2, 3 -> 3, 4 -> 4)                                           //> m  : scala.collection.immutable.map[int,int] = map(1 -> 1, 2 -> 2, 3 -> 3, 4                                           //|  -> 4) val l = list(1,2,3,4)                     //> l  : list[int] = list(1, 2, 3, 4) val v = vector(1,2,3,4)                   //> v  : scala.collection.immutable.vector[int] = vector(1, 2, 3, 4)  m.exists(_._1 == 3)                       //> res0: boolean = true m.contains(3)                             //> res1: boolean = true l.exists(_ == 3)                          //> res2: boolean = true l.contains(3)                             //> res3: boolean = true v.exists(_ == 3)                          //> res4: boolean = true v.contains(3)                             //> res5: boolean = true

intuitively, assume vectors should quickest random checks, , lists quickest if 1 knows value checked in beginning of list , there lot of data. however, confirmation or correction welcome. also, please feel free expand other data structures.

note: please let me know if feel question vague i'm not sure phrasing correctly.

set , map (with default hash table implementation) far fastest @ contains since compute hash value , jump right location immediately. example, if want find arbitrary string out of list of thousand, contains on set 100x faster contains on list or vector or array.

with exists, care how fast collection traverse--you have traverse anyway. there, list champ (unless want traverse array hand), set , on particularly bad (e.g. exists on list ~8x faster on set when each have 1000 elements). others within 2.5x of list (usually 1.5x, vector has underlying tree structure not fast traverse).


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