Redis:如何解析列表结果 [英] Redis: How to parse a list result

问题描述

我正在像这样在 Redis 中存储一个列表:

I am storing a list in Redis like this:

redis.lpush('foo', [1,2,3,4,5,6,7,8,9])

然后我会像这样返回列表:

And then I get the list back like this:

redis.lrange('foo', 0, -1)

我得到了这样的东西:

[b'[1, 2, 3, 4, 5, 6, 7, 8, 9]']

如何将其转换为实际的 Python 列表?

How can I convert this to actual Python list?

此外，我在 RESPONSE_CALLBACKS 中没有看到任何可以提供帮助的定义?我错过了什么吗?

Also, I don't see anything defined in RESPONSE_CALLBACKS that can help? Am I missing something?

一个可能的解决方案(在我看来很糟糕)可以是:

A possible solution (which in my opinion sucks) can be:

result = redis.lrange('foo',0, -1)[0].decode()

result = result.strip('[]')

result = result.split(', ')

# lastly, if you know all your items in the list are integers
result = [int(x) for x in result]

更新

好的，我找到了解决方案.

Ok, so I got the solution.

实际上，lpush 函数期望将所有列表项作为参数传递，而不是作为单个列表传递.redis-py 源码中的函数签名说的很清楚...

Actually, the lpush function expects all the list items be passed as arguments and NOT as a single list. The function signature from redis-py source makes it clear...

def lpush(self, name, *values):
    "Push ``values`` onto the head of the list ``name``"
    return self.execute_command('LPUSH', name, *values)

我在上面所做的是发送一个列表作为参数，然后将其作为单个项目发送到 redis.

What I am doing above is send a single list as an argument, which is then sent to redis as a SINGLE item.

我应该按照答案中的建议打开列表:

I should be unpacking the list instead as suggested in the answer:

redis.lpush('foo', *[1,2,3,4,5,6,7,8,9])

返回我期望的结果...

which returns the result I expect...

redis.lrange('foo', 0, -1)
[b'9', b'8', b'7', b'6', b'5', b'4', b'3', b'2', b'1']

推荐答案

我认为您遇到的语义类似于 list.append() 和 list 之间的区别.扩展().我知道这对我有用:

I think you're bumping into semantics which are similar to the distinction between list.append() and list.extend(). I know that this works for me:

myredis.lpush('foo', *[1,2,3,4])

... 注意列表前面的 *(map-over)运算符！

... note the * (map-over) operator prefixing the list!

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