CODEWITHSUNDEEP
clojuresequenceinfinitelazy-sequences
Mate Varga
Mate Varga

Reputation: 3416

Clojure: iterating on multiple (possibly infinite) sequences

I've got a couple of infinite sequences. I want to take one of each other per step. What's the idiomatic way of doing that? In other words, assume that there's a finite, realized sequence iss that contains lazy, infinite sequences. How to print out the first elements of every infinite sequence, then the second element of every infinite sequence, and so on?

Upvotes: 1

Views: 313

Answers (2)

soulcheck
soulcheck

Reputation: 36767

I'd use a simple map vector. It returns a lazy sequence of applications of vector to the first elements of all the sequences, then the second elements and so on. Until you force realization, nothing get's mapped.

Try it for yourself (note that (range) returns an infinite lazy seq):

(def lazy-zipped (map vector (range) (drop 10 (range)) (drop 20 (range))))

(take 5 lazy-zipped)

prints

([0 10 20] [1 11 21] [2 12 22] [3 13 23] [4 14 24])

Upvotes: 3

user100464
user100464

Reputation: 18429

Maybe this?

user=> (def seq1 (iterate inc 1))
#'user/seq1
user=> (def seq2 (iterate inc 10))
#'user/seq2
user=> (take 10 (partition 2 (interleave seq1 seq2)))
((1 10) (2 11) (3 12) (4 13) (5 14) (6 15) (7 16) (8 17) (9 18) (10 19))

Upvotes: 1

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