使用Swift array.count和arc4random()

Question

为了让这段代码有效,我错过了什么？nodesLeft是[Int].

let x = nodesLeft.count
let r = Int(arc4random_uniform(x))

我收到一个错误:

操场执行失败:错误:: 136:40:错误:'NSNumber'不是'UInt32'的子类型让r = Int(arc4random_uniform(x))

Answer 1

我遇到了同样的问题arc4random_uniform(); 它的参数必须是一个UInt32投下x这样:

let x = UInt32(nodesLeft.count)
let r = Int(arc4random_uniform(x))