字典

/*
         字典是以键值对的形式来存储数据的
         字典里可以存储任意类型数据
         字典里存储的数据顺序是不确定的
         不可变字典里相同的key，后面的key-value无效；可变字典里相同的key会覆盖以前的值
         */
        //不可变数组
        //创建字典
        NSDictionary * dic1 = [NSDictionary dictionaryWithObjectsAndKeys:@"name",@"zhangsan", nil];
        NSLog(@"dic1为：%@",dic1);
        
        //便捷方式创建字典
        NSDictionary * dic2 = @{@"name":@"lisi",@"age":@"14",@"height":[NSNumber numberWithInt:170],@"dic1":dic1,@"age":@"40"};
        NSLog(@"dic2为：%@",dic2);
        
        //获取字典的长度
        NSLog(@"dic的长度为:%ld",dic2.count);
        
        //获取字典中的值
        NSString * str = [dic2 objectForKey:@"name"];
        NSLog(@"dic2中key为name的值是%@",str);
        
        //遍历字典
        NSArray * keys = [dic2 allKeys];
        for (int i = 0; i<keys.count; i++) {
            NSLog(@"%@ = %@",keys[i],[dic2 objectForKey:keys[i]]);
        }
        
        NSEnumerator * enumerator =[dic2 objectEnumerator];
        id value;
        while (value = [enumerator nextObject]) {
            NSLog(@"value = %@",value);
        }
        
        //可变数组
        //创建可变数组
        NSMutableDictionary * mutableDic1 = [[NSMutableDictionary alloc]initWithCapacity:0];
        //向可变数组添加元素
        [mutableDic1 setObject:@"wangwu" forKey:@"name"];
        [mutableDic1 setObject:@"男" forKey:@"sex"];
        [mutableDic1 setObject:@"nv" forKey:@"sex"];
        NSLog(@"可变数组mutableDic1：%@",mutableDic1);
        
        //删除元素
        [mutableDic1 removeObjectForKey:@"sex"];
        NSLog(@"可变数组mutableDic1：%@",mutableDic1);
        
        //删除所有元素
        [mutableDic1 removeAllObjects];
        NSLog(@"可变数组mutableDic1：%@",mutableDic1);