黑马程序员－－OC基础－－NSDictionary用法

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 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 }