Clojure - How to return a sequence?

2
votes

p-seq: Receives two integer arguments, “from” and “to”, and this method should return a sequence containing only the numbers given by is-p function between “from” and “to”. The current code that I have written only prints out all the numbers between "from" and "to". I want p-seq to return a sequence.

is-p: checks and returns true if a number is a prime number otherwise returns false.

(defn p-seq [from to]
  (loop [count from]
    (if (> count to)
      (println "")
      (do
        (def seqf (is-p count))
          (if(= seqf true)
            (print count " ")
            )
  (recur (inc count))))))

Any help appreciated. Thank you.

2
clojure

2 Answers

1
votes

Since you have a predicate function is-prime? you could simply use it to filter the range of all numbers between from and to:

(filter is-prime? (range 100 200))
=> (101 103 107 109 113 127 131 137 139 149 151 157 163 167 173 179 181 191 193 197 199)

Note the upper bound argument to range is exclusive.

1
votes

You simply can use filter function on sequence, filter is applied on each element

given is-p function that checks prime number, 

user=> (filter is-p (range 1 20))
(2 3 5 7 11 13 17 19)

So, your p-seq function looks like, 

user=> (defn p-seq [from to]
          (filter is-p (range from to)))
#'user/p-seq

user=> (p-seq 100 200)
(101 103 107 109 113 127 131 137 139 149 151 157 163 167 173 179 181 191 193 197 199)

references

https://clojuredocs.org/clojure.core/range

https://clojuredocs.org/clojure.core/filter