ios - 扩展 where 子句中的 ArrayType
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<pre><code>extension Array where Element: _ArrayType, Element.Generator.Element: Any {
func transpose() -> {
if self.isEmpty { return () }
let count = self.count
var out = (repeating: Element(), count: count)
for outer in self {
for (index, inner) in outer.enumerated() {
out.append(inner)
}
}
return out
}
}
</code></pre>
<p>从 Swift 2.2 转换后，我在 Swift 3.0 中遇到此错误。数组的元素也是数组。那么在 Swift 3.0 中如何定义呢？</p></p>
<br><hr><h1><strong>Best Answer-推荐答案</ strong></h1><br>
<p><pre><code>extension Array where Element : Collection, Element.Index == Int, Element.IndexDistance == Int {
func transpose() -> [] {
typealias InnerElement = Element.Iterator.Element
if self.isEmpty { return [] }
let count = self.count
var out = [](repeating: (), count: count)
for outer in self {
for (index, inner) in outer.enumerated() {
out.append(inner)
}
}
return out
}
}
</code></pre></p>
<p style="font-size: 20px;">关于ios - 扩展 where 子句中的 ArrayType，我们在Stack Overflow上找到一个类似的问题：
<a href="https://stackoverflow.com/questions/39366534/" rel="noreferrer noopener nofollow" style="color: red;">
https://stackoverflow.com/questions/39366534/
</a>
</p>
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