conj

Append to list.

(conj [1] 2) ;; [1 2]

conj seq vs conj vector

It works differently with vectors and seqs

(conj [1] 2)       ;; [1 2]
(conj (seq [1]) 2) ;; [2 1]

or with an empty collection:

(conj (conj []  1) 2) ;; [1 2]
(conj (conj nil 1) 2) ;; (2 1)

Be careful when using conj with functions that return a string:

(conj (drop-last [ 1 "_" ]) 2)       ;; [2 1]
(conj (vec (drop-last [ 1 "_" ])) 2) ;; [1 2]

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• Tag: clojure