Question

Inside a loop, I’m trying to set the value as the object’s key. Not sure how to do this:

@user = {"username"=>"123", "full_name"=>"John Doe"}

@account = Account.new
@user.keys.each { |key|
  @account.key = @user[key]
}

That returns an error of: NoMethodError: undefined method `key=’

Answer 1

Function calls in Ruby act like message-passing. So what you are looking for is send.

The @account object in your example is not a Hash like @user, it is a Class instance.

But Rails has an even better way to initialize a Model with attributes:

@account = Account.new(username: '123', full_name: 'John Doe')

In a Rails controller, these are usually in the params hash if you wrote your form correctly:

@account = Account.new(params[:user])

If you must do it manually, you can:

@account = Account.new

# set all attributes at once
@account.attributes = @user

# this also works, but it's the least desirable
@user.each {|key, value| @account.send("#{key}=", value) }

The last example works because @account.key = value is actually syntactic sugar for a method call: @account.key=(value)

I highly recommend reading through Rails Form Helpers and building your forms how it suggests.