variable find_by_attribute?

Could someone please tell me how I can use find_by_attribute with a variable which defines what kind of attribute I am looking for?

For instance,

    @answer = User.first.answer
    User.last.find_by_attribute(@answer)

The answer attribute has the type string

I hope someone can show me how this 开发者_如何学运维could work

EDIT

I just realised that this doesn't doesn't get me the results I'm looking for... Here's actually what I need: the name of the attribute I'm trying to access from another user is stored in the answer attribute. So I would need something like User.@answer ... but this doesn't work of course

EDIT2

Okay here the solution to my problem:

    @answer = User.first.answer
    User.last.send("#{@answer}")
    => true

Okay here the solution to my problem:

    @answer = User.first.answer
    User.last.send("#{@answer}")

You need to know which attribute you are querying for in order to use the dynamic finders, e.g.

User.find_by_answer(@answer).last