Error : ClassCastException

Question

Hi!

I have an error in my console that points to my function :

 (defn sales-by-customer [name-cus]
   (->> sales_2
       (filter #(= (second %) name-cus))
       (map #(* (Integer/parseInt (last %)) (Double. (products_2 (second %)))))
       (reduce +)
    )
  )

sales_2 : [id customers_name products_name quantity]

([1 Sara candies 3] 
 [2 Joe jam 3]
 [3 Sara gum 1])

products_2 : {products_name price}

({candies 6.0} {gum 4.5} {jam 45.1})

Basically, what I'm trying to do is, when I call (sales-by-customer "Sara"), I want to get the sum of Sara's purchases, which is in this case : (36.0 + 14.5) and display the result.

When I call my function, I get the following error message :

 Syntax error (ClassCastException) compiling at (db.clj:76:1).
class clojure.lang.LazySeq cannot be cast to class clojure.lang.IFn (clojure.lang.LazySeq and clojure.lang.IFn are in unnamed module of loader 'app')

Any idea how to solve this error?
I'm supposed to get a number.. I don't know where the cast error occurs...

Thanks!

Answer 1

you are calling products_2 as a function, and it is a seq of maps, not a function, which is what the class cast exception there means.

a map can be invoked as a function, but a seq of maps cannot