Clojure Koans Answers and Explanations - 1 - Equalities

Answers with brief explanations to Clojure Koans on equality. 

Let's roll our sleeves and start real simple.

The koan is given first, brief explanation and solution follow.

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;1

(= __ true)

; In clojure true is true so the answer would be  true

(= true true)

(= (not false) true) ; :-) unnecessary extra

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;2

(= __ (+ 1 1))

; answer matches with exercise number 

; conspiracy theorists - this is a golden opportunity :-)

(= 2 (+ 1 1)

    

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;3

(= (+ 3 4) __ (+ 2 __))

; let's reduce the way we did in primary school

(= (+ 3 4) 7)

; so the expression is

(= 7 _ (+ 2 _))

; of many things possible, it is evident that

; only 7 would be equalt to 7

(= 7 7 (+ 2 _))

; and then what do you have to add to 2 to make it = to 7?

(= 7 7 (+ 2 5))

; placing back

(= (+ 3 4) 7 (+ 2 5))

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;4

(= 2 2/1 __)

; Clojure reduces the fraction to their lowest factors

; 21/3 = 7 AND

; 24/20 = 6/5

(= 2 2/1 4/2)

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;5

(= __ (= 2 2.0))

; floats and ints have markedly different representations

; internally and generally bad idea to have computations

; like this one

(= false (= 2 2.0)

    

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;5    

(== 2.0 2 __)

; this one is a pure value comparison

; in this case values are equivalent

; so we can use any of 4/2 2/1 2.0 or 2

(== 2.0 2 4/2)

(== 2.0 2 2/1)

(== 2.0 2 2.0)

(== 2.0 2 2)

  

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 ;6

(not= :fill-in-the-blank __))

; instructive to think of this as

; ! equals() of Java

(not= :fill-in-the-blank false)

(not= :fill-in-the-blank true))