CODEWITHSUNDEEP
filterclojure
No3l
No3l

Reputation: 11

Filtering in Clojure

I have a map like this

(def invoice 
{:productId ["001" "002" "003" "004" "005" "006" "007" "008" "009" "010"],
:price ["50" "60" "70" "50" "40" "45" "55" "90" "50" "70"],
:quantity ["0" "0" "1" "2" "0" "0" "0" "0" "0" "1"]})

how can i filter so it only show product id where the quantity is 1 or more ?

i already tried to make like this

(filter (> (invoice :quantity %) 1) (map list (invoice :price) (invoice :quantity) (invoice :productid))

but it doesn't work

Upvotes: 1

Views: 539

Answers (3)

user2946753
user2946753

Reputation: 41

Usually, data is easier to deal with when it's a little more 'normal' so you don't have to worry about indices like in your sample. I'd reccomend storing it as a seq of ({:id x :price y :quant z} ... ).

This function does that:

(defn invoices [invoice]
  (map (fn [id price quant]
          {:id id
           :price price
           :quant quant})  (:prouctId invoice)
                           (:price invoice)
                           (:quantity invoice))

Then from there you can simply

(->> invoice 
     invoices 
     (remove #(= "0" (:price %))  ;; remove "0" prices
     (map :id))) ;; get ids

assuming that your dataset doesn't have negative quantities.

Upvotes: 0

Shawn Zhang
Shawn Zhang

Reputation: 1884

first step would be construct a pair of Product ID and quantity:

(map vector (invoice :quantity) (invoice :productId))
;; ["0" "001"] .... first element would be quantity and second is productiID

second step would be filter out which quantity is greater than 0, here I use (Integer. xx) to conver the quantity to a number.

(filter #(> (Integer. (first %)) 0) (map vector (invoice :quantity) (invoice :productId)))

Upvotes: 1

Lee
Lee

Reputation: 144136

You need to create a function to pass as the first argument to filter. Secondly, you need to parse the quantities before you do the comparison to 1, which you can do using read-string:

(filter #(> (read-string (second %)) 1) (map list (invoice :price) (invoice :quantity) (invoice :productId)))

Upvotes: 2

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