字典类

//1.创建字段,不可变的
        NSDictionary * dic = [NSDictionary dictionaryWithObjectsAndKeys:@"xiaozhe",@"name", nil];
        NSLog(@"dic %@",dic);

        //2.快捷创建方式
        NSDictionary * dic2 = @{ @"one":@"1",@"two":@"2"};
        NSLog(@"dic2 %@",dic2);

        //3.字典中可以存任意数据类型
        // 字典的顺序不是自然顺序
        NSArray * array = @[@"one",@"two"];

        NSDictionary * dic3 = @{
                                @"one":@"1",
                                @"num":[NSNumber numberWithInt:10],
                                @"aaa":dic2,
                                @"bbb":dic,
                                @"ar1":array

                                };

        NSLog(@"dic3 %@",dic3);

        //4.获得字典的长度
        NSLog(@"count %ld",dic3.count);

        //5.从字典中取值

        NSString * str  = [dic3 objectForKey:@"one"];
        NSLog(@"str %@",str);

        NSDictionary * dicTmp = [dic3 objectForKey:@"aaa"];
        NSLog(@"dicTmp %@",dicTmp);
        NSArray * arrayTmp = [dic3 objectForKey:@"ar1"];
        NSLog(@"arrayTmp %@",arrayTmp);

        //6.遍历

        //取出所有的key值
        NSArray * allkeys = [dic3 allKeys];
        NSLog(@"allkeys %@",allkeys);

        for (int i = 0; i < allkeys.count; i++)
        {
            NSString * key = [allkeys objectAtIndex:i];

            //如果你的字典中存储的多种不同的类型,那么最好用id类型去接受它
            id obj  = [dic3 objectForKey:key];
            NSLog(@"obj %@",obj);
        }

        //2.枚举器

        NSEnumerator * enumerator =  [dic3 objectEnumerator];

        id value;
        while (value = [enumerator nextObject]) {
            NSLog(@"value %@",value);
        }