Swift 给数组元素赋值

var array = [1,2,3]

// 不可以
// Cannot assign to property: 'number' is a 'let' constant
for number in array {
	number = 3
}

// 常规的
for index in 0..<array.count {
    array[index] = 3
}

// 优雅的
array.enumerated().forEach {
    array[$0.offset] = 3
}