Foundation框架之NSDictionary的使用

 1 /**
 2  OC中            JAVA中
 3  NSArray          List
 4  NSSet            Set
 5  NSDictionary     Map
 6  
 7  集合
 8  1.NSArray\NSMutableArray
 9  * 有序
10  * 快速创建(不可变):@[];
11  * 快速访问元素:数组名[i];
12  
13  2.NSSet\NSMutableSet
14  * 无序
15  
16  3.NSDictionary\NSMutableNSMutable
17  * 无序
18  * 快速创建(不可变):@{key1 : value1, key2 : value2}
19  * 快速访问元素:字典名[key];
20  */
21 
22 
23 #import <Foundation/Foundation.h>
24 
25 int main(int argc, const char * argv[]) {
26     @autoreleasepool {
27     
28     /**
29      key ---> value     键值对
30      索引 ---> 文字内容
31      */
32         /** 字典的创建方式1 */
33         NSDictionary *dict1 = [NSDictionary dictionaryWithObject:@"Chris Paul" forKey:@"name"];
34         id obj1 = [dict1 objectForKey:@"name"];
35         NSLog(@"%@", obj1);
36         
37         /** 字典的创建方式2 */
38         NSArray *keys1 = @[@"name", @"address"];
39         NSArray *objects = @[@"Chris Paul", @"Los Angeles"];
40         NSDictionary *dict2 = [NSDictionary dictionaryWithObjects:objects forKeys:keys1];
41         id obj2 = [dict2 objectForKey:@"address"];
42         NSLog(@"%@", obj2);
43         
44         /** 字典的创建方式3 */
45         NSDictionary *dict3 = [NSDictionary dictionaryWithObjectsAndKeys:@"Chris Paul", @"name", @"Los Angeles", @"Address", nil];
46         id obj3 = [dict3 objectForKey:@"name"];
47         NSLog(@"%@", obj3);
48         
49         /** 字典的创建方式4:快速创建（Xcode新特性）*/
50         NSDictionary *dict4 = @{@"name" : @"Chris Paul", @"address" : @"Los Angeles"}; /** @{@“id objec” : id, ... }返回值是NSDictionary */
51         id obj4 = dict4[@"address"]; /** 此方法又是Xcode的新特性 */
52         NSLog(@"%@", obj4);
53         
54         /** 字典键值对的访问 */
55         NSLog(@"%ld", dict4.count);
56         
57         /** 可变字典的创建 */
58         NSMutableDictionary *dict5 = [NSMutableDictionary dictionary];
59         [dict5 setObject:@"Chris Paul" forKey:@"name"]; /** 添加键值对 */
60         [dict5 setObject:@"Los Angeles" forKey:@"address"]; /** 添加键值对 */
61         [dict5 setObject:@"Magic Johnson" forKey:@"name"]; /** 此时，会覆盖Chris Paul*/
62         NSLog(@"%@", dict5[@"name"]);
63         [dict5 removeObjectForKey:@"address"]; /** 移除键值对 */
64         NSLog(@"%@", dict5[@"address"]);
65         
66         /** 字典的遍历方法1 */
67         NSDictionary *dict6 = @{@"name" : @"Chris Paul",
68                                 @"address" : @"Los Angeles",
69                                 @"name2" : @"Chris Paul"};
70                 /** 注意:
71                  1.字典不允许有相同的key，但允许有相同的value(object)
72                  2.字典是无序的
73                  */
74         NSArray *keys2 = [dict6 allKeys]; /** 这个方法打印出来是乱的 */
75         NSLog(@"%@", keys2);
76         for (int i = 0; i<dict6.count; i++) {
77             NSString *key = keys2[i];
78             NSString *object = dict6[keys2];
79             NSLog(@"%@---%@", key, object);
80         }
81         
82         /** 字典的遍历方法2:block */
83         [dict6 enumerateKeysAndObjectsUsingBlock:^(id key, id obj, BOOL *stop) {
84             NSLog(@"%@---%@", key, obj);
85         }];
86     }
87     return 0;
88 }