CODEWITHSUNDEEP
clojure
zetafish
zetafish

Reputation: 2412

How to combine sequences in clojure?

I have the following sequences

(def a [1 2 3 4])
(def b [10 20 30 40])
(def c [100 200 300 400])

I want to combine the sequences element by element:

(...  + a b c)

To give me:

[111 222 333 444]

Is there a standard function available to do so? Or alternatively what is a good idiomatic way to do so?

Upvotes: 9

Views: 717

Answers (2)

Jeremy
Jeremy

Reputation: 22435

The function you are looking for is map.

(map + [1 2 3 4] [10 20 30 40] [100 200 300 400])
;=> (111 222 333 444)

Note that map returns a lazy sequence, and not a vector as shown in your example. But you can pour the lazy sequence into an empty vector by using the into function.

(into [] (map + [1 2 3 4] [10 20 30 40] [100 200 300 400]))
;=> [111 222 333 444]

Also, (for completeness, as it is noted in another answer) in Clojure 1.4.0+ you can use mapv (with the same arguments as map) in order to obtain a vector result.

Upvotes: 15

number23_cn
number23_cn

Reputation: 4629

if you use clojure-1.4.0 or above, you can use mapv:

user> (mapv + [1 2 3 4] [10 20 30 40] [100 200 300 400])
[111 222 333 444]

Upvotes: 16

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