IOS开发－ObjC－NSString

  1 /    NSString
  2 //    NSString *string1 = [NSString stringWithString:@"appbear"];
  3 //    NSLog(@"%@",string1);
  4     
  5     
  6     NSString *string2 = @"bearapp";
  7     NSLog(@"%@",string2);
  8   
  9     
 10     NSString *string3 = [NSString stringWithFormat:@"today is %d",5];
 11     NSLog(@"%@",string3);
 12     
 13 //    连接两个字符串
 14     NSString *string4 = [NSString stringWithFormat:@"today is %@",string2];
 15     NSLog(@"%@",string4);
 16     
 17     
 18 //    判断string是不是一样
 19     NSString *codeString = @"cocochina123";
 20     NSString *codeString2 = @"cocochina123";
 21     
 22     if ([codeString isEqualToString:codeString2]) {
 23         NSLog(@"两个字符串相等");
 24     }else{
 25         NSLog(@"两个字符串不相等");
 26     }
 27     
 28 //    比较地址是否相同
 29     if (codeString2==codeString) {
 30         NSLog(@"==");
 31     }else{
 32         NSLog(@"!=");
 33     }
 34     
 35 //    大小写转换
 36 //    全部转化为大写
 37     NSString *up = [codeString uppercaseString];
 38     NSLog(@"%@",up);
 39 //    全部转化为小写
 40     NSString *low = [codeString2 lowercaseString];
 41     NSLog(@"%@",low);
 42 //    全部首字母大写
 43     NSString *cap = [string4 capitalizedString];
 44     NSLog(@"%@",cap);
 45     
 46     
 47     
 48     NSString *stri1 = @"abcdefg";
 49     NSString *stri2 = @"bbcdefg";
 50     if (stri1==stri2) {
 51         NSLog(@"两个字符串相同");
 52     }else{
 53         NSLog(@"两个字符串不同");
 54     }
 55     if ([stri1 isEqualToString:stri2]) {
 56         NSLog(@"两个字符串equal");
 57     }else{
 58         NSLog(@"两个字符串not equal");
 59     }
 60 //    NSComparisonResult是一个枚举量
 61     NSComparisonResult resut = [stri1 caseInsensitiveCompare:stri2];
 62     
 63     NSLog(@"%ld",resut);
 64     */
 65     //    截取字符串
 66     NSString *string1 = @" 今 天 天晴 了       ";
 67     NSString *string2 = @" 今天 天阴 了 ";
 68     NSLog(@"%@",[string1 substringFromIndex:2]);
 69     NSLog(@"%@",[string2 substringToIndex:2]);
 70     
 71     NSRange range = {1,3};
 72     NSLog(@"%@",[string1 substringWithRange:range]);
 73     
 74     //    拼接两个字符串
 75     NSString * lastOutString = [string1 stringByAppendingString:string2];
 76     NSLog(@"%@",lastOutString);
 77     
 78     //    去掉字符串两头的空格
 79     NSString *lastTrimString = [string1 stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]];
 80     NSLog(@"%@",lastTrimString);
 81     
 82     
 83     //    替换字符串的内容
 84     NSString *replace = [string1 stringByReplacingOccurrencesOfString:@"今天" withString:@"昨天"];
 85     NSLog(@"%@",replace);
 86     
 87     
 88     //    搜索字符串第一种方法
 89     NSRange range1 = [string1 rangeOfString:@"天晴"];
 90     if (range1.location!=NSNotFound) {
 91         NSLog(@"找到天晴了");
 92     }else{
 93         NSLog(@"没找到天晴");
 94     }
 95     
 96     //    搜索字符串第二种方法
 97     NSRange range2 = [string1 rangeOfString:@"天晴"];
 98     if (range2.length!=0) {
 99         NSLog(@"找到天晴了%lu，%lu",(unsigned long)range2.location,(unsigned long)range2.length);
100     }else{
101         NSLog(@"没找到天晴");
102     }