OC基本对象类型

一、NSString

1.NSString 不可变字符串里面的内容无法更改

  1 //1.如何创建字符串对象
  2         NSString *str = @"Jack" ;
  3         NSLog(@"----%@",str);
  4         
  5         //创建一个空的字符串对象 创建之后对象里面的内容是不能被改变的
  6         //尽量不用
  7         NSString *str2 = [[[NSString alloc] init] autorelease];
  8         NSString *str2_ = [NSString string];
  9         NSLog(@"----%@",str2);
 10         
 11         //用已经存在的字符串对象去创建一个新的对象
 12         NSString *str3 = [[[NSString alloc] initWithString:str] autorelease];
 13         NSString *str3_ = [NSString stringWithString:str];//工厂方法
 14         
 15         //按照一定的格式拼接字符串 字符串里面的值由一些变量决定
 16         int age = 10;
 17         NSString *name = @"Rose";
 18         NSString *str4 = [[[NSString alloc] initWithFormat:@"%@ is %d years old!", name, age] autorelease];
 19         NSString *str4_ = [NSString stringWithFormat:@"%@ is %d years old!", name, age];
 20         NSLog(@"%@", str4);
 21         
 22         //length 判断字符串是否为空 视频1G
 23         NSLog(@"%lu -- %@ ",str4.length, str4);
 24 
 25 //查找子字符串
 26         NSString *des = @"The NSString class and its mutable subclass";
 27         
 28         //从index -> 结尾
 29         NSString *s1 = [des substringFromIndex:4];
 30         //从开头 -> index 不包含index对应的字符
 31         NSString *s2 = [des substringToIndex:5];
 32         
 33         //NSRange range = {4,8};//c语言的方式
 34         //某个范围的子字符串
 35         NSRange range = NSMakeRange(4, 8);
 36         NSString *s3 = [des substringWithRange:range];
 37         NSLog(@"%@", s3);
 38         
 39         //字符串的比较 @"123456"
 40         NSString *passwd = @"123";
 41         if ([passwd isEqualToString:@"123456"]) {
 42             NSLog(@"the same");
 43         } else{
 44             NSLog(@"not the same");
 45         }
 46         
 47         NSString *addr = @"a";
 48         NSComparisonResult result = [addr compare:@"b"];
 49         if (result == NSOrderedAscending) {
 50             NSLog(@" < ");
 51         } else if (result == NSOrderedSame){
 52             NSLog(@" = ");
 53         } else{
 54             NSLog(@" > ");
 55         }
 56         
 57         //两个对象的比较
 58         NSString *ob1 = @"Jack";
 59         NSString *ob2 = @"jacken";
 60         
 61         Person *p1 = [[Person new] autorelease];
 62         Person *p2 = [[Person new] autorelease];
 63         //注意：p1和p2不是一个对象 只是名字相同而已
 64 //        p1.name = @"Jack";
 65 //        p2.name = @"Jack";
 66 
 67         //当一个对象被添加到一个集合里面(NSArray NSDictionary NSSet)
 68         //这个对象的引用计数+1
 69         NSArray *pArray = @[p1];
 70         p1.name = @"Jack";
 71         
 72         NSLog(@"%@", ((Person *)pArray[0]).name);
 73         
 74         if ([p1 isEqual:pArray[0]]) {
 75             NSLog(@"是同一个对象");
 76         } else{
 77             NSLog(@"不是同一个对象");
 78         }
 79 
 80 //前缀和后缀
 81         NSString *url = @"http:png//f.hiphotos.baidu.com/image/h%3D300/sign=16e69d830f4f7png8f09f0b9cf349300a83/63d0f703918fa0ece5f167da2a9759ee3d6ddb37.png";
 82         if ([url hasSuffix:@".jpg"]){
 83             NSLog(@"是一个图片");
 84         }
 85         
 86         if ([url hasPrefix:@"http:"]) {
 87             NSLog(@"是一个网址");
 88         }
 89         
 90         //是否包含某一个字符串
 91         //快来看我的视频 t.dfafaf.v 快给我点赞哦
 92         if ([url containsString:@"baidu.com"]) {
 93             NSLog(@"是百度的资源");
 94         }
 95         
 96         //后去某个字符串在源字符串里面的具体位置
 97         NSRange r = [url rangeOfString:@"png"];
 98         if (r.length == 0){
 99             NSLog(@"不存在");
100         } else{
101             NSLog(@"存在:%lu %lu", r.location, r.length);
102         }
103 
104 //在一个字符串后面追加一个字符串形成新的字符串
105 //        @"abc" @"de"
106 //        @"abcde"
107         NSString *hStr = @"abc";
108         NSString *newStr = [hStr stringByAppendingString:@"de"];
109         NSString *newStr2 = [hStr stringByAppendingFormat:@"my name is %@", name];
110         NSLog(@"%@ %@", hStr, newStr);
111         
112         //字符串的数字 转化为对应的类型doubleValue floatValue
113         NSString *numStr = @"123";
114         int num = [numStr intValue];
115         
116         NSString *ntr = [NSString stringWithFormat:@"%d", age];

2.NSMutableString 可变字符串内容可以被更改

 1 //NSMutableString 可变字符串 insert delete change
 2         NSMutableString *mStr = [[NSMutableString alloc] initWithCapacity:0];
 3         NSMutableString *mStr_ = [NSMutableString stringWithCapacity:0];
 4         NSLog(@"%@", mStr);
 5         
 6         //字符串的追加
 7         [mStr appendString:@"Hello"];
 8         NSLog(@"%@", mStr);
 9         
10         [mStr appendFormat:@" my name is %@", name];
11         NSLog(@"%@", mStr);
12         
13         //字符串的插入
14         [mStr insertString:@"World " atIndex:6];
15         NSLog(@"%@", mStr);
16         
17         //替换
18         NSRange rg = [mStr rangeOfString:@"Rose"];
19         [mStr replaceCharactersInRange:rg withString:@"Jack"];
20         NSLog(@"%@", mStr);
21         
22         //删除数据
23         [mStr deleteCharactersInRange: NSMakeRange(0, 12)];
24         NSLog(@"%@", mStr);
25         
26         //重新设置内容
27         [mStr setString:@"abc"];
28         NSLog(@"%@", mStr);
29         
30         /*
31          NSCaseInsensitiveSearch = 1,    //不区分大小写比较
32          NSLiteralSearch = 2,    //逐字节比较 区分大小写
33          NSBackwardsSearch = 4,    //从字符串末尾开始搜索
34          */
35         [mStr replaceOccurrencesOfString:@"ABC" withString:@"one two three" options:NSLiteralSearch range:NSMakeRange(0, 3)];
36         NSLog(@"%@", mStr);

二、NSArray

1.注意：1⃣️OC的数组只能存放对象类型不能存放C语言的基本数据类型

　　 2⃣️OC的数组可以存放多种对象类型的数据【@"dfa", @2, pxd, cc, shuzu】
　　 3⃣️不能存NSNull的数据

猜你喜欢