黑马程序员－－OC基础－－NSDictionary用法

 1 #import <Foundation/Foundation.h>
 2 
 3 
 4 /*
 5  字典：
 6  key－－>value
 7  索引－－>文字内容
 8  
 9  里面存储的东西都是键值对
10  
11  
12  */
13 
14 int main() {
15     //不可变，初始化需完成赋值
16     NSDictionary *dict = [NSDictionary dictionaryWithObject:@"jack" forKey:@"name"];
17     
18     id obj = [dict objectForKey:@"name"];
19     
20     NSLog(@"%@", obj);
21     
22     
23     NSArray *keys = @[@"name",@"address"];
24     NSArray *objects = @[@"jack", @"北京"];
25     
26     NSDictionary *dict2 = [NSDictionary dictionaryWithObjects:objects forKeys:keys];
27     id obj1 = [dict2 objectForKey:@"name"];
28     
29     NSLog(@"%@", obj1);
30     
31     
32     NSDictionary *dict3 = [NSDictionary dictionaryWithObjectsAndKeys:@"jack", @"name",
33                            @"北京", @"address",
34                            @"34234234", @"qq", nil];
35     
36     id obj2 = [dict3 objectForKey:@"qq"];
37     
38     NSLog(@"%@", obj2);
39     
40     
41     //建议使用
42     NSDictionary *dict4 = @{@"name" : @"jack",
43                             @"address" : @"北京",
44                             @"qq" : @"4234234"};
45     
46     //id obj3 = [dict4 objectForKey:@"address"];
47     
48     //建议使用
49     id obj3 = dict4[@"address"];
50     
51     NSLog(@"%@", obj3);
52     
53     //返回键值对的个数
54     NSLog(@"%ld", dict4.count);
55     
56     
57     
58     
59     //可变字典
60     NSMutableDictionary *dict5 = [NSMutableDictionary dictionary];
61     //添加键值对，无序
62     [dict5 setObject:@"jack" forKey:@"name"];
63     [dict5 setObject:@"北京" forKey:@"address"];
64     
65     //重复给key赋值会覆盖以前的值,字典不允许相同的key，允许有相同的object
66     [dict5 setObject:@"rose" forKey:@"name"];
67     
68     //删除键值对
69     //[dict5 removeObjectForKey:@"name"];
70     
71     
72     //遍历
73     NSDictionary *dict6 = @{@"name" : @"tom",
74                             @"address" : @"北京",
75                             @"tel" : @"3423424"};
76 //    NSArray *Keys = [dict6 allKeys];
77 //    
78 //    for (int i = 0; i<dict6.count; i++) {
79 //        
80 //        NSString *key = Keys[i];
81 //        NSString *object = dict6[key];
82 //        NSLog(@"%@=%@", key, object);
83 //    }
84     
85     //block遍历
86     [dict6 enumerateKeysAndObjectsUsingBlock:^(id key, id obj, BOOL *stop) {
87         NSLog(@"%@-%@", key, obj );
88         
89         *stop = YES;
90         
91         }];
92     
93       return 0;
94 }