I am trying to store two integers and a double from User Input into a list in Clojure. Any and all help is greatly appreciated!

My standard input to the console: 12 1 5.30.

Here is my code:

(ns clojure.partial.map
(:gen-class))

(defn string-to-list [s]
  (re-seq #"\d \d (\d )?\.(\d )?" s))

(defn convert-seq-of-int-to-strings [ss]
  (let [new_partition (partition-all 2 ss)
       map-one (map #(Integer/parseInt %) (take 1 new_partition))
       map-two (map #(Double/parseDouble %) (take 1 (drop 1 new_partition)))
       map-concat (concat (map-one map-two))]
   (doseq [item map-concat]
   (println item)))

(def user-input (read-line))

(def new-sequence (string-to-list new-line))

(def converting-seq-to-list (convert-seq-of-int-to-strings new-seq))

; Expected Output: 
; 12
; 1
; 5.30

Error Message:

Execution error (ClassCastException) at clojure.partial.map/convert-seq-of-int-to-strings.
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')

CodePudding user response：

There is actually much more errors than one let, but let's start from that:

• You're missing parentheses around let and missing brackets around bindings in this let.
• (concat (map-one map-two)) is causing this exception: class clojure.lang.LazySeq cannot be cast to class clojure.lang.IFn. map-one isn't function, so you should call this concat like this: (concat map-one map-two)
• Regex in string-to-list can't parse your string "5 10 2.84". You could rewrite that into something like this:

(->> (re-seq #"\d (\.\d )?" "5 10 2.84")
     (map first))
=> ("5" "10" "2.84")

Or even more readable clojure.string/split:

(clojure.string/split "5 10 2.84" #" ")
=> ["5" "10" "2.84"]

• I don't understand why you need to use partition, so I will skip this one.
• Replace Integer/parseInt and Double/parseDouble with parse-long and parse-double. You will actually need only one, because parse-double also handles strings without a decimal dot. Or you can use clojure.edn/read-string, if you want to get numbers of desired types.
• Your function convert-seq-of-int-to-strings actually returns nil, as result of doseq. And its name is misleading, you're converting a sequence of strings into a sequence of numbers.

With all these changes, your code could look like this:

(defn input-to-seq []
  (let [numbers (->> (clojure.string/split (read-line) #" ")
                     (mapv clojure.edn/read-string))]
    (doseq [item numbers]
      (println item))
    numbers))

CodePudding user response：

You forgot the square brackets in the let statement. Also, use (round) parentheses outside of the let. Example:

(let [a 1
      b 2
      c (  a b)]
  (println "c =" c))

Just guessing on what you want. Here is one possible solution, built using my favorite template project:

(ns tst.demo.core
  (:use demo.core tupelo.core tupelo.test)
  (:require
    [clojure.edn :as edn]
    [clojure.string :as str]
    [schema.core :as s]))

(verify
  (let [input-str  "1 2 3.0"
        tokens     (str/split input-str #"\s ")
        result     (vec (for [token tokens]
                          (edn/read-string token)))]
    (is= result [1 2 3.0])))