字符串

来源：互联网发布：大数据软件平台编辑：程序博客网时间：2024/06/17 19:58

##字符串 ##

1.字符串的格式化（格式化字符串）

 int age = 20;        NSString *name = @"程真";        NSString  *info = [NSString   stringWithFormat:@"%@今年%d", name, age];        NSLog(@"%@", info);

2、截取哪一个位置的字符串

a. 从哪个位置开始截取字符串

index不是下标所以不从0开始

NSString *newString = [info substringFromIndex:2];        NSLog(@"%@", newString);         NSString  *message = @"锄禾日当午，汗滴和下图，。。。";         NSString  *newString1 = [message  substringFromIndex:12];        NSLog(@"%@", newString1);

b. 截取字符串到哪个位置

NSString  *newString2 = [message  substringToIndex:12];         NSLog(@"%@", newString2);        NSString  *newString3 = [message  substringToIndex:5];        NSLog(@"%@", newString3);

c.截取字符串从哪到哪

     NSRange range;    range.location = 6;    range.length  = 5;   NSLog(@"%@", [message  substringWithRange:range]);     NSRange range1;    range1.location = 5;    range1.length  = 7;    NSLog(@"%@", [message  substringWithRange:range1]);

3.把字符串通过指定字符分隔成数组

NSString *result = @"武松打虎 duang！duang！duang! 老虎跑下山 ya~ya~ya~";    NSArray  *laoHu = [result componentsSeparatedByString:@" "];    NSLog(@"%@", laoHu[3]);

4.把所有英文字母转成大写

     NSString  *str = @"bRuce";    NSLog(@"%@", str.uppercaseString);

5.把所有英文字母转成小写

    NSString  *str1 =@"ADFAEFCD";    NSLog(@"%@", str1.lowercaseString);

6.首字母大写

NSLog(@”%@”, str.capitalizedString);

7.拼接字符串

   a.stringWithFormat        NSString *ss = @"我是";        NSString  *ss2 = @"好人";      b.stringByAppendingString        NSLog(@"%@", [ss  stringByAppendingString:ss2]);      c.stringByAppendingFormat NSLog(@"%@",[ss stringByAppendingFormat:@"%@不止一天两天", ss2]);

8.判断字符串是否包含某个字符串

 NSString  *sss =@"上山打老虎跑了";   NSRange  range119 =  [sss  rangeOfString:@"老虎"];        if (range119.location  != NSNotFound) {            NSLog(@"%@", sss);        }else{            NSLog(@"骗人~~~~");        }

9.字符串以什么开始（头部包含什么内容）

if ([sss hasPrefix:@”上山”] != NO) {
NSLog(@”存在”);
}else{
NSLog(@”error”);
}

10.字符串以什么结束（尾部包含什么内容）

  if ([sss hasSuffix:@"老虎跑了1"] != NO) {            NSLog(@"存在");        }else{            NSLog(@"error");        }

11.可变字符串

 NSMutableString  *name1 = [[NSMutableString   alloc]initWithString:@"Bruce"];        NSRange  range110 ;        range110.location = 1;        range110.length  =  4;

a. 把指定位置的字符串替换成另一个字符串

    [name1 replaceCharactersInRange:range110 withString:@"blue" ];        NSLog(@"%@", name1);       NSMutableString  *ssss = [NSMutableString  stringWithString:@"我是一名程序员"];        range110.location = 4;        range110.length   = 3;        [ssss  replaceCharactersInRange:range110 withString:@"医生"];        NSLog(@"%@", ssss);

b. 删除指定位置的字符串

 range110.location = 0;        range110.length   = 4;        [ssss deleteCharactersInRange:range110];        NSLog(@"%@", ssss);

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