Swift开发String+NSString详细使用

//

//  ViewController.swift

//  Swift+String

import UIKit

class ViewController: UIViewController {

override func viewDidLoad() {

super.viewDidLoad()

//var 变量  let常量  就不过多叙述了

self.view.backgroundColor = UIColor.yellow;

let my:NSString = "My name"

let name = " is 辉哥"

var myName = ""

let myfirst:NSString = "我的 名字"

myName = (my as String) + name

print(myName)

//计算字符串的长度

print(myfirst.length)//nsstring类型字符串

print(myName.characters.count)//string类型字符串

//获取字符串位置

var strA = "中国是最强大的国家"

let startindex = strA.startIndex//获取起始位置

print(startindex)

let endIndex = strA.endIndex//获取终止位置

print(endIndex)

let char = strA[strA.index(after: startindex)]//获取某个下标后一个下标对应的字符

print(char)

let char2 = strA[strA.index(before: endIndex)]//获取某个下标前一个下标对应的字符

print(char2)

let subString = strA[startindex...strA.index(startindex, offsetBy: 4)]//通过范围获取字符串中的某一个子串

print(subString)

let num = strA.range(of: "最强大")//获取某字符串在父串中的范围

print(num)

strA.append(" 世界上的")//追加字符串操作

print(strA)

strA.insert("~", at: strA.index(strA.startIndex, offsetBy: 10))//在指定位置出阿如一组字符

print(strA)

strA.replaceSubrange(strA.startIndex...strA.index(strA.startIndex, offsetBy: 9), with: "我们大中国永远屹立在")//在指定范围替换一个字符串

print(strA)

strA.remove(at: strA.index(before: strA.endIndex))//在指定位置删除一个字符

print(strA)

strA.removeSubrange(strA.startIndex...strA.index(strA.startIndex, offsetBy: 2))

print(strA)

var strB = "myname"

strB = strB.uppercased()//全部转为大写

print(strB)

strB = strB.lowercased()//全部转为小写

print(strB)

//字符串的连接

//string 型字符串

let str1:String = "上"

let str2:String = "海"

//使用" + "号连接两个字符串

var str3:String = str1 + str2

print(str3)

//在字符串的末尾拼接字符串,代替str3.extend("123456789")

str3.write("123456789")

print(str3)

//字符串比较

//sting型字符串

let str4:String = "SHANGHAI"

let str5:String = "shanghai"

//判断连个字符串是否相等

let bl1:Bool = str4 == str5

print(bl1)

//判断字符串是否为空

let bl2:Bool = str4.isEmpty

print(bl2)

//判断字符串前缀

let bl3:Bool = str4.hasPrefix("SHANG")

print(bl3)

//判断字符串后缀

let bl4:Bool = str4.hasSuffix("HAI")

print(bl4)

//比较两个字符串

let result1:ComparisonResult = str4.compare(str5)

print(result1)

//忽略大小写比较

let result2:ComparisonResult = str4.caseInsensitiveCompare(str5)

print(result2)

//NSSting 型字符串

let str6:NSString = "shanghai"

let str7:NSString = "SHANGHAI"

//判断两个字符串是否相等

let bl5:Bool = str6.isEqual(str7)

print(bl5)

//判断字符串前缀

let bl6:Bool = str6.hasPrefix("shang")

print(bl6)

//判断字符串后缀

let bl7:Bool = str6.hasSuffix("hai")

print(bl7)

//忽略大小写比较

let result3:ComparisonResult = str6.compare(str7 as String)

print(result3)

let result4:ComparisonResult = str6.caseInsensitiveCompare(str7 as String)

print(result4)

//字符串切割

//Sting 型字符串

let str11:String = "dong$fang$ming$zhu"

//字符串 按照字符切割

let arr1:Array = str11.components(separatedBy: "$")

print(arr1)

//自动按照" / "分割字符串  NSString特有,string没有

let str13:NSString = "Users/JHQ0228/Desktop"

let arr3:Array = str13.pathComponents

print(arr3)

//字符串与数字的相互转换   有一些用的比较少,就当做了解一下吧

// String 型字符串

// 字符 转 数字

let charr:Character = "A";

var charVal1:Int = 0

// 遍历字符转换为的字符串

for charStr in String(charr).unicodeScalars {

// 将取出的字符转换为 Int 型数字

charVal1 = Int(charStr.value)

}

// 字符串 转 数字

// 数字型字符串 转 Int 型数字，代替 intStr.toInt()

let intStr:String = "64";           let intVal1:Int? = Int(intStr)

// 数字 转 字符

let intVal2 = 65;                   let charVal2:Character = Character(UnicodeScalar(intVal2)!)

// 数字 转 字符串

// Int 型数字 转 字符串

let intVal3:Int = 123;              let intStr1:String = intVal3.description

// Int32 型数字 转 字符串

let int32Val1:Int32 = 32;           let int32Str1:String = int32Val1.description

// Int64 型数字 转 字符串

let int64Val1:Int64 = 64;           let int64Str1:String = int64Val1.description

// Float 型数字转 字符串

let floatVal1:Float = 2.1;          let floatStr1:String = floatVal1.description

// Double 型数字转 字符串

let doubleVal1:Double = 162.1;      let doubleStr1:String = doubleVal1.description

// Bool 型 转 字符串

let boolVal1:Bool = true;           let boolStr1:String = boolVal1.description

// NSString 型字符串

// 字符串 转 数字

// 字符串 转 Int 型数字

let intVal4:Int = NSString(string: "6432").integerValue

// 字符串 转 Int32 型数字

let int32Val2:Int32 = NSString(string: "32").intValue

// 字符串 转 Int64 型数字

let int64Val2:Int64 = NSString(string: "64").longLongValue

// 字符串 转 Float 型数字

let floatVal2:Float = NSString(string: "2.1").floatValue

// 字符串 转 Double 型数字

let doubleVal2:Double = NSString(string: "162.1").doubleValue

// 字符串 转 Bool 型

let boolVal2:Bool = NSString(string: "false").boolValue

// Do any additional setup after loading the view, typically from a nib.

}

override func didReceiveMemoryWarning() {

super.didReceiveMemoryWarning()

// Dispose of any resources that can be recreated.

}

}