Vector operations in Clojure

Builds a ferry route as a vector, then reads it by index, count, and slice.

;; a vector literal is written with square brackets
(def legs ["quarry" "ridge" "hollow" "ferry"])

;; conj adds to the end of a vector and hands back a new one
(def route (conj legs "depot"))

;; nth reads by position, and a vector is itself a function of its index
(println (nth route 0) "then" (route 1))
(println "legs:" (count route))

;; subvec takes a slice that shares the original storage
(println "middle:" (subvec route 1 3))

;; vectors compare by value, so an equal slice is equal
(println (= ["quarry" "ridge"] (subvec route 0 2)))

How it works

1. (conj legs "depot") returns a new vector with the stop added at the end.
2. (nth route 0) and (route 1) both read by position, since a vector is a function of its index.
3. (subvec route 1 3) takes a slice, and = shows that vectors compare by value.

Keywords and builtins used here

• conj
• count
• def
• nth
• println
• route
• subvec

The run, in numbers

Lines

15

Characters to type

545

Tokens

71

Three-star pace

75 tpm

At the three-star pace of 75 tokens a minute, this run takes about 57 seconds.

Type this snippet

Step 1 of 3 in Collections, step 4 of 27 in Language basics.

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Vector operations in other languages

• C++