如何直接将数组中的所有字符串大写？

我学得很快。我一直在游乐场尝试这个。我不知道为什么这里的字符串没有大写。或者有没有其他方法可以直接将数组内的字符串大写？

这是我的代码。

var dogNames = ["Sean", "fido", "Sarah", "Parker", "Walt", "abby", "Yang"]

for index in 0..<dogNames.count {
    var dogName = dogNames[index].capitalizedString
    dogNames.removeAtIndex(index)
    dogNames.append(dogName)
}

当我尝试再次显示变量dogNames时。里面的字符串没有大写。

update: Xcode 8.2.1 • 斯威夫特 3.0.2

var dogNames = ["Sean", "fido", "Sarah", "Parker", "Walt", "abby", "Yang"]

for (index, element) in dogNames.enumerated() {
    dogNames[index] = element.capitalized
}

print(dogNames)   // "["Sean", "Fido", "Sarah", "Parker", "Walt", "Abby", "Yang"]\n"

这是一个典型的使用案例map():

let dogNames1 = ["Sean", "fido", "Sarah", "Parker", "Walt", "abby", "Yang"].map{$0.capitalized}

A filter() sample:

let dogNamesStartingWithS = ["Sean", "fido", "Sarah", "Parker", "Walt", "abby", "Yang"].filter{$0.hasPrefix("S")}

dogNamesStartingWithS   // ["Sean", "Sarah"]

你可以结合两者：

let namesStartingWithS = ["sean", "fido", "sarah", "parker", "walt", "abby", "yang"].map{$0.capitalized}.filter{$0.hasPrefix("S")}

namesStartingWithS   // ["Sean", "Sarah"]

如果需要，您还可以使用 sort 方法（如果不想改变原始数组，则使用排序方法）按字母顺序对结果进行排序：

let sortedNames = ["sean", "fido", "sarah", "parker", "walt", "abby", "yang"].map{$0.capitalized}.sorted()

sortedNames  // ["Abby", "Fido", "Parker", "Sarah", "Sean", "Walt", "Yang"]