具有容量的Swift初始化数组 [英] Swift init Array with capacity

问题描述

如何快速初始化具有特定容量的阵列?

How do I initialize an Array in swift with a specific capacity?

我尝试过:

var grid = Array <Square> ()
grid.reserveCapacity(16)

但收到错误

expected declaration 

推荐答案

怎么样:

class Square {

}

var grid = Array<Square>(count: 16, repeatedValue: Square());

尽管这将为每个正方形调用构造函数.

Though this will call the constructor for each square.

如果使数组具有可选的Square实例，则可以使用:

If you made the array have optional Square instances you could use:

var grid2 = Array<Square?>(count: 16, repeatedValue: nil);

---

使用Swift3，此初始值设定项签名已更改为以下:

var grid3 = Array<Square>(repeating: Square(), count: 16)

或

var grid4 = [Square](repeating: Square(), count: 16)

当然，两者都可以与Square?和nil一起使用.

Of course, both also work with Square? and nil.

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