样例1:
let temStr1 = "this is first sentence. this is second sentence."
print(temStr1.capitalized)
This Is First Sentence. This Is Second Sentence.
样例2:
let temStr2 = "this is first sentence. this is second sentence."
print(temStr2.capitalizingFirstLetter())
This is first sentence. This is second sentence.
结论：如果只是标题需要做成样例1，是句子需要做成样例2。
说明：
1. capitalized是swift 系统属性；
2.capitalizingFirstLetter是字体String的拓展方法，如下：
extension String {
func capitalizingFirstLetter() -> String {
return prefix(1).capitalized + dropFirst()
}
mutating func capitalizeFirstLetter() {
self = self.capitalizingFirstLetter()
}
}
标签：String,sentence,capitalizingFirstLetter,样例,大写,首字母,second,swift From： https://www.cnblogs.com/akiha/p/16727087.html