遍历集合，数组和字典

 1、字典的遍历

NSDictionary *dict = @{@"name": @"luoguankun",@"address":@"北京"};

//通过for循环遍历NSDictionary，不推荐
NSArray *keys = [dict allKeys];
for (int i = 0; i < keys.count ; i++) {
    NSString *value = [dict objectForKey:keys[i]];
    NSLog(@"%@---%@",keys[i],value);
}

//推荐使用这种遍历方式，通过block遍历集合
[dict enumerateKeysAndObjectsUsingBlock:^(id key, id obj, BOOL *stop) {
    NSLog(@"%@-%@",key,obj);

    //打印一次就停止
    *stop = YES;
}];
2、数组的遍历
for循环遍历
NSArray *array1 = @[@"a",@"b",@"c",@"d",@"f",@"g"];

//普通的for循环
for(int i = 0; i < array.count; i++)
{

}

id obj 代表着集合中的每一个元素
for(id obj in array1)
{
    //找出obj元素在数组中的位置
    unsigned long i = [array1 indexOfObject:obj];

    NSLog(@"%ld=%@",i,obj);
}

[array1 enumerateObjectsUsingBlock:
    ^(id obj, NSUInteger idx, BOOL *stop) {
        NSLog(@"%ld = %@", idx,obj);

        if(idx == 2)
        {
            *stop = YES;
        }
    }
];