get model attribute dynamically in rails 3

问题

How can I get the attribute from the model object dynamically? I have the attribute of the User object as string:

u = User.find(1)

Can I do something like u.get("user_id")

回答1:

You could try using the ActiveRecord model instance like a hash.

u = User.find(1)
name = u[:name]
field = "first_name"
first_name = u[field]

回答2:

Yet another approach:

attr = :first_name
@user.read_attribute attr  

回答3:

Try this

user = User.find(1)

then something like this should do what you require

user.send('field_name')

回答4:

Try this

u = User.find(1)
attr = "first_name"
u.send(attr)

回答5:

Not sure if I totally understand your questions. Try something like:

User.find(1).name

if you mean you only want to fetch from DB specific attribute you can do:

User.find(1,:select => :name)

来源：https://stackoverflow.com/questions/5996455/get-model-attribute-dynamically-in-rails-3