NSMutableDictionary 可变字典 . NSDictionary 不可变字典

    //    不可变字典
    //    1.创建
    NSDictionary *dic = [NSDictionary dictionaryWithObject:@"value"forKey:@"key"];  //  一个键一个值
    //    NSArray *a =
    //    NSArray *b =
    
    NSDictionary *dic1 = [NSDictionary dictionaryWithObjects:@[@"v1",@"v2",@"v3"] forKeys:@[@"k1",@"k2",@"k3"]];
    
    //    直接dic1的内容给dic2
    NSDictionary *dic2 = [NSDictionary dictionaryWithDictionary:dic1];
    
    //    NSDictionary *dic2 = [NSDictionary dictionaryWithObjectsAndKeys:@"v1",@"k1",@"v2",@"k2", nil];
    //    数组的最简写法@[];
    //    字典的最简写法 @{key:value}
    //    NSDictionary *dic3 = @{
    //                        key:value,
    //                           };
    //    NSDictionary *dic2= [NSDictionary dictionaryWithObjects:<#(nonnull NSArray *)#> forKeys:<#(nonnull NSArray<id<NSCopying>> *)#>]
    
    //    arry.count
    //    获取字典的数量
    int a = [dic1 count];
    NSLog(@"%d",a);
    
    //    通过指定的key获取我们的value(最重要)
    NSString * str= [dic1 objectForKey:@"k3"];
    NSLog(@"%@",str);
    
    //  取得字典中所有的key跟value
    [dic1 allKeys];
    [dic1 allValues];

//    可变字典
//    1.创建
//    直接赋值
    NSMutableDictionary *mDic = [NSMutableDictionary dictionaryWithObjectsAndKeys:@"v1",@"k1",@"v2",@"k2", nil];
    
//    实例方法/对象方法（开辟一个空间并赋值）
    NSMutableDictionary *mDic1 = [[NSMutableDictionary alloc]initWithObjectsAndKeys:@"v1",@"k1",@"v2",@"k2", nil];
   
//    创建一个空的字典
    NSMutableDictionary *dic2 = [NSMutableDictionary dictionary];
    
//    向子典中添加新的value，key
    [mDic setValue:@"dfs" forKey:@"1"];
//    [mDic setObject:@"" forKey:<#(nonnull id<NSCopying>)#>];
//    NSLog(@"%@",mDic);
    
//    可以删除key(只要删除key不用删除value)
//    [mDic removeObjectForKey:@"k1"];
//    NSLog(@"%@",mDic);
    
//    删除多个key
    NSArray *arr = [NSArray arrayWithObjects:@"k1",@"k2", nil];
//    [mDic removeObjectsForKeys:arr];
//    NSLog(@"%@",mDic);
    
//    删除全部
//    [mDic removeAllObjects];
    
//    遍历
    for (NSString *key in mDic) {
       NSString *ob = [mDic objectForKey:key];
        NSLog(@"%@",ob);
    }
    
    for (int index = 0;index<mDic.count;index++){
        NSString *obc = [mDic1 objectForKey:[[mDic1 allKeys]objectAtIndex:index]];
    
    }