Swift字符串的拼接、插值、删除编辑操作
一、字符串拼接
//字符串拼接
let str1 = "hello "
let str2 = "word"
var str = ""
str = str1 + str2//字符串拼接
print("The joining together of two strings:\(str)")//打印输出: The joining together of two strings:hello word
//将一个字符串添加到另一个字符串的尾部
let exclamationMark:Character = "!"
str.append(exclamationMark)//将一个字符串添加到另一个字符串的尾部
print("使用append拼接一个字符:\(str)")//打印输出: 使用append拼接一个字符:hello word!
//使用append拼接
let subStr = "word"
str.append(subStr)
print("使用append拼接一个子字符串:\(str)")//打印输出: 使用append拼接一个子字符串:hello word!word
二、字符串插入
//字符串插入一个字符
var welcome = "hello"
welcome.insert("!", at: welcome.endIndex)//插入一个字符
print("insertNewCharacters:\(welcome)\n");//打印输出: insertNewCharacters:hello!
//插入一个子字符串
welcome.insert(contentsOf: " word", at: welcome.index(before: welcome.endIndex))//插入一个子字符串
print("insertNewSubStr:\(welcome)\n")//打印输出: insertNewSubStr:hello word!
//字符串插值
let addend = 6
let sumStr = "\(addend) add 8.1 is \(Double(addend) + 8.1)"
print(sumStr)//打印输出: 6 add 8.1 is 14.1
三、字符串删除
//删除最后一个字符
welcome.remove(at: welcome.index(before: welcome.endIndex))//删除最后一个字符
print("removeStrLastCharacters:\(welcome)\n")//打印输出: removeStrLastCharacters:hello word
//删除规定范围内的子串
let range = welcome.index(welcome.endIndex, offsetBy: -6)..<welcome.endIndex
welcome.removeSubrange(range)//删除规定范围内的子串
print("removeStrRange:\(welcome)\n")//打印输出: removeStrRange:hell
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