//1.分割
        
        NSString *urlString = @"www.beiwoit.com";
        
        /**
         *  将参数作为分隔符,将字符串分割成若干部分
         */
        NSArray *array = [urlString componentsSeparatedByString:@"."];
        
        NSLog(@"%@",array);
        
        //2.获取字符
        char character = [urlString characterAtIndex:4];
        
        NSLog(@"%c",character);
        
        //3.截取 substring
        
            //截取到下标(不包括下标字符)
        NSLog(@"%@",[urlString substringToIndex:5]);
            //自下标截取(包括下标字符)
        NSLog(@"%@",[urlString substringFromIndex:5]);
            //范围截取
        /**
         *  typedef struct _NSRange {
                    NSUInteger location;//位置 -> 下标 -> 4
                    NSUInteger length;//长度 -> 长度 -> 7
            } NSRange;
         */
        
        //c创建结构体
//        NSRange range1 = {4,7};
        
        //oc创建结构体
        NSRange range = NSMakeRange(4, 7);
        
        NSLog(@"%@",[urlString substringWithRange:range]);
        
        
        //4.拼接  appending
        NSString *appString = @"拼接字符串:";
        
            //拼接字符串
        NSLog(@"%@",[appString stringByAppendingString:@"尾端添加字符串"]);
        
            //拼接格式化字符串
        NSLog(@"%@",[appString stringByAppendingFormat:@"尾端添加格式化字符串%d",100]);
        
            //拼接扩展名 .pdf
        NSLog(@"%@",[appString stringByAppendingPathExtension:@"dmg"]);
        
            //拼接路径  /path
        NSLog(@"%@",[appString stringByAppendingPathComponent:@"dmg"]);
        
        
        //5.查找
        NSString *findString = @"/Users/CORYIL/Library/Developer/CoreSimulator/Devices/88A633A0-6294-4853-80DE-8060C1580820/data/Containers/Data/Application/84CE535F-49D1-498E-89DB-2F07C50D6A24/Documents/";
        
        NSRange findResult = [findString rangeOfString:@"Documents"];
        
        //将结构体转化为字符串 NSStringFromXXX(结构体)
        NSLog(@"%@",NSStringFromRange(findResult));
        
        
        //6.替换 replacing
        
            //根据range替换
        NSString *newString = [findString stringByReplacingCharactersInRange:findResult withString:@"嘿嘿"];
        
        NSLog(@"%@",newString);
        
            //直接替换
        NSLog(@"%@",[findString stringByReplacingOccurrencesOfString:@"Users" withString:@"用户们"]);


2016-01-18 20:11:35.733 02NSString字符串[4039:618330] (
    www,
    beiwoit,
    com
)
2016-01-18 20:11:35.733 02NSString字符串[4039:618330] b
2016-01-18 20:11:35.733 02NSString字符串[4039:618330] www.b
2016-01-18 20:11:35.733 02NSString字符串[4039:618330] eiwoit.com
2016-01-18 20:11:35.733 02NSString字符串[4039:618330] beiwoit
2016-01-18 20:11:35.733 02NSString字符串[4039:618330] 拼接字符串:尾端添加字符串
2016-01-18 20:11:35.734 02NSString字符串[4039:618330] 拼接字符串:尾端添加格式化字符串100
2016-01-18 20:11:35.734 02NSString字符串[4039:618330] 拼接字符串:.dmg
2016-01-18 20:11:35.734 02NSString字符串[4039:618330] 拼接字符串:/dmg
2016-01-18 20:11:35.734 02NSString字符串[4039:618330] {161, 9}
2016-01-18 20:11:35.734 02NSString字符串[4039:618330] /Users/CORYIL/Library/Developer/CoreSimulator/Devices/88A633A0-6294-4853-80DE-8060C1580820/data/Containers/Data/Application/84CE535F-49D1-498E-89DB-2F07C50D6A24/嘿嘿/
2016-01-18 20:11:35.735 02NSString字符串[4039:618330] /用户们/CORYIL/Library/Developer/CoreSimulator/Devices/88A633A0-6294-4853-80DE-8060C1580820/data/Containers/Data/Application/84CE535F-49D1-498E-89DB-2F07C50D6A24/Documents/
Program ended with exit code: 0