変数の値の入れ替え

うまくいかない方法

code:jl

a, b = 1, 2

a = b; b = a

a, b # (2, 2)

直感的な方法

code:jl

a, b = 1, 2

a, b = b, a

a, b # (2, 1)

よくある方法

code:jl

a, b = 1, 2

temp = a # 一時変数にaの値を退避させる

a = b

b = temp

a, b # (2, 1)

算術演算による方法

code:jl

a, b = 1, 2

a = a + b

b = a - b # (a + b) - b

a = a - b # (a + b) - (a + b - b)

a, b # (2, 1)

論理演算による方法

code:jl

a, b = 1, 2

a = a ⊻ b # 0b00000001 ⊻ 0b00000010 = 0b00000011

b = a ⊻ b # 0b00000011 ⊻ 0b00000010 = 0b00000001

a = a ⊻ b # 0b00000011 ⊻ 0b00000001 = 0b00000010

a, b # (2, 1)