1.String的切割
例如:
let name: String = "zhangsan"
// 1.获取下标,从开始位置'z',往后移动一个位置,就是'h'的位置了
let subIndex = name.index(name.startIndex, offsetBy: 1)
let subIndex2 = name.index(name.startIndex, offsetBy: 4)
// 2.根据下标获取某个字符
let subStr = name[subIndex] //Character类型: h
// 3.获取中间某部分字符串
let midStr = name[subIndex...subIndex2] // hang
// 4.获取前面某部分
let preStr = name[...subIndex] // zh
// 5.获取后面某部分
let posStr = name[subIndex...] // hangsan
吐槽,实在是太难用了,我们写个扩展吧
extension String {
func mySubString(_ index1: Int, _ index2: Int) -> String {
let subIndex1 = self.index(self.startIndex, offsetBy: index1)
let subIndex2 = self.index(self.startIndex, offsetBy: index2)
return String(self[subIndex1...subIndex2])
}
func getCharAt(_ index: Int) -> Character {
let subIndex = self.index(self.startIndex, offsetBy: index)
return self[subIndex]
}
}
使用:
let name: String = "zhangsan"
let str1 = name.mySubString(0, 1)
let char1 = name.getCharAt(2)
print("char1",char1) // char1 a
print("str1",str1) // str1 zh
2.字符Character变Int
let value: UInt32 = String(subStr).unicodeScalars.first!.value
吐槽,这也太啰嗦了吧,自己写个扩展
extension Character {
func toInt() -> Int {
return Int(String(self).unicodeScalars.first!.value)
}
}
使用:
let value2 = subStr.toInt()
3.String 和 Array的转换
在一些场景中,操作String,不如操作Array方便,操作完之后,再转回String
let arr = Array(name)
print(arr)
let arrStr = String(arr[0...4])
print(arrStr)