Question

I am going through some Clojure tutorials using Closure Box, and entered the following code:

user> (def stooges (vector "Moe" "Larry" "Curly"))
#'user/stooges
user> (contains? stooges "Moe")
false

Shouldn’t this evaluate to TRUE ? Any help is appreciated.

Answer 1

A vector is similar to an array. contains? returns true if the key exists in the collection. You should be looking for the “key/index” 0, 1 or 2

user=> (def stooges (vector "Moe" "Larry" "Curly"))
#'user/stooges
user=> (contains? stooges 1)
true
user=> (contains? stooges 5)    
false

If you were using a hash…

user=> (def stooges {:moe "Moe" :larry "Larry" :curly "Curly"})
#'user/stooges
user=> (contains? stooges :moe)
true
user=> (contains? stooges :foo)
false

As mikera suggests, you probably want something like clojure.core/some