iOS-OC-基础-NSDictionary常用方法

  1     /*=============================NSDictionary(不可变字典)的使用=========================*/
  2     
  3     //————————————————————————————————字典的创建————————————————————————————————
  4     
  5     // 前面的是值(value)，后面的是键(key)，一一对应
  6     // 方式一：
  7     NSDictionary *dic = [[NSDictionary alloc] initWithObjectsAndKeys:@"value",@"key",@"value1",@"key1", nil];
  8     NSLog(@"dic :%@",dic);
  9     
 10     // 方式二：
 11     NSDictionary *dic1 = [NSDictionary dictionaryWithObjectsAndKeys:@"value",@"key",@"value1",@"key1", nil];
 12     
 13     // 字典的value可以说任何对象类型
 14     NSArray *array = @[@"11",@"22",@"33"];
 15     NSDictionary *dic2 = [[NSDictionary alloc] initWithObjectsAndKeys:array,@"key" ,nil];
 16     NSLog(@"dic2 :%@",dic2);
 17     
 18     NSDictionary *dic3 = [[NSDictionary alloc] initWithObjectsAndKeys:dic2,@"dicKey", nil];
 19     NSLog(@"dic3 :%@",dic3);
 20     
 21     // 方式三：跟方式一区分,只能是不可变字典
 22     NSDictionary *dic4 = @{@"key":@"vlaue",@"key1":@"value1"};
 23     NSLog(@"dic4 :%@",dic4);
 24     
 25     
 26     //————————————————————————————————字典的常用方法—————————————————————————————
 27     
 28     // count 字典元素的个数，键值一起为一个元素
 29     NSUInteger len =  [dic4 count];
 30     NSLog(@"len = %ld",len);
 31     
 32     //objectForKey :根据key取对应的值，如果可以没有不会报错，返回的是null
 33     id obj = [dic3 objectForKey:@"dicKey"];
 34     NSLog(@"obj:%@",obj);
 35     
 36     //allKeys 获取字典的所有key,返回的是数组
 37     NSArray *allKeys = [dic4 allKeys];
 38     NSLog(@"allKeys :%@",allKeys);
 39     
 40     //allValues 获取字典的所有Value,返回的是数组
 41     NSArray *allValues = [dic4 allValues];
 42     NSLog(@"allValues: %@",allValues);
 43     
 44     //allKeysForObject 获取相同value的所有key
 45     NSDictionary *dic5 = @{@"key":@"value",@"key1":@"value"};
 46     NSArray *allKey = [dic5 allKeysForObject:@"value"];
 47     NSLog(@"allKey :%@",allKey);
 48     
 49     
 50     /*=============================NSMutableDictionary(可变字典)的使用=========================*/
 51     
 52     //————————————————————————————————可变字典的创建————————————————————————————————
 53     
 54     // 两种方式：
 55     NSMutableDictionary *mDic = [[NSMutableDictionary alloc] initWithObjectsAndKeys:@"abc",@"key",@"hhhh",@"key1", nil];
 56     
 57     NSMutableDictionary *mDic1 = [NSMutableDictionary dictionaryWithObjectsAndKeys:@"value",@"key",@"value1",@"key1", nil];
 58     
 59     //NSMutableDictionary *mDic2 = @{@"key":@"value",@"key1":@"value1"}; 错误:不能这样创建可变字典
 60     NSLog(@"mDic1:%@",mDic1);
 61     
 62     
 63     //————————————————————————————————可变字典的常用方法—————————————————————————————
 64     
 65     //setObject:forKey 给字典添加元素，修改元素
 66     [mDic1 setObject:@"value2" forKey:@"key2"];
 67     NSLog(@"mDic1:%@",mDic1);
 68     // 修改key 对应的元素
 69     [mDic1 setObject:@"kkkkk" forKey:@"key2"];
 70     
 71     //removeObjectForKey 移除指定键的元素
 72     [mDic1 removeObjectForKey:@"key"];
 73     NSLog(@"mDic1:%@",mDic1);
 74     
 75     // removeAllObjects 移除字典所有的元素
 76     [mDic1 removeAllObjects];
 77     NSLog(@"mDic1:%@",mDic1);
 78     
 79     // removeObjectsForKeys 移除一组键对应的元素
 80     NSArray *keys = [mDic1 allKeys];
 81     [mDic1 removeObjectsForKeys:keys];
 82     NSLog(@"mDic1:%@",mDic1);
 83     
 84     //setDictionary 将新字典替换旧字典
 85     [mDic1 setDictionary:mDic];
 86     NSLog(@"mDic1 :%@",mDic);
 87     
 88     
 89     /*===========================================字典的遍历===================================*/
 90     
 91     NSMutableDictionary *mDic3 = [[NSMutableDictionary alloc] initWithObjectsAndKeys:@"abc",@"key",@"etrtr",@"key1", nil];
 92     
 93     // 1、普通遍历
 94     NSArray *allkey = [mDic3 allKeys];
 95     for (int i = 0; i < mDic3.count; i++) {
 96         
 97         NSString *key = [allkey objectAtIndex:i];
 98         NSString *value = [mDic3 objectForKey:key];
 99         NSLog(@"---%@",value);
100     }
101     
102     // 2、快速遍历 obj 是字典的key
103     for (id obj in mDic3) {
104         
105         NSString *value = [mDic3 objectForKey:obj];
106         NSLog(@"==%@",value);
107     }
108     
109     // 3、block 遍历
110     [mDic3 enumerateKeysAndObjectsUsingBlock:^(id key, id obj, BOOL *stop) {
111         
112         NSLog(@">>%@",key);
113         NSLog(@">>%@",obj);
114     }];
本文GitHub地址https://github.com/zhangkiwi/iOS_SN_NSDictionary