我不明白以下情况:
let a1: [[Double]] = [[1]]
let equ1 = a1 == a1 // This builds
let t1: (Double, Double) = (1, 1)
let equ2 = t1 == t1 // This builds also
let a2: [[(Double, Double)]] = [[(1,1)]]
let equ3 = a2 == a2 // This gives a build error
构建错误是
Binary operator '==' cannot be applied to two '[[(Double, Double)]]' operands
Double
为什么我可以检查2 的元组的二维数组是否相等Doubles
,但不能检查这个元组的二维数组是否相等?