xcode - How does swift infer that num1 and num2 are integers? -
i confused on how swift infers num1
, num2
integers. function accepting array of ints, true, how swift num1
, num2
related array of ints???
func mean4 (numbers: [ int ] ) -> double { let sum = numbers.reduce(0, combine: { num1, num2 in return num1 + num2 04: })
the reduce
function defined as:
extension sequencetype { public func reduce<t>(initial: t, @noescape combine: (t, self.generator.element) -> t) -> t }
self.generator.element refers array element type, int. means num2
int. initial value 0
passed, can infer t
int well.
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