Swift Array（重复：，计数:)行为 [英] Swift Array(repeating:, count:) behaviour

问题描述

为什么 labels 数组中只有一个元素显示为 view 的子视图，特别是在使用<$时c $ c> Array（repeating :, count：）？

Why does only one element from the labels array appear as a subview of view, specifically when using Array(repeating:, count:)?

let labels = Array(repeating: UILabel(), count: 7)

print(labels.count) //7

let view = UIView()

for label in labels {
    view.addSubview(label)
}

print(view.subviews.count) //1

推荐答案

之所以会这样，是因为 Array（repeating：count：）创建了一个由7个变量组成的数组，这些数组指向相同的标签。

This happens because Array(repeating:count:) creates an array of 7 variables that are pointing to the same label.

由于所有7个元素都指向同一实例，因此子视图的计数为1。

Since all 7 elements are pointing to the same instance, the count of the subviews will be 1.

这篇关于Swift Array（重复：，计数:)行为的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！