Rails: Copying attributes from an object to another using the “attributes” method

Question

Let model Quote have attributes [price, description]

Let model Invoice have attributes [price, description, priority]

Answer 1

How about the slice method from ActiveSupport?

quote = Quote.new(invoice.attributes.slice(:price, :description))

or even

quote = Quote.new(invoice.attributes.slice(*Quote.accessible_attributes))

Answer 2

You can select only the attributes that Quote has:

Quote.new(invoice.attributes.select{ |key, _| Quote.attribute_names.include? key })

As noted by @aceofspades (but not with a dynamic solution), you can use ActiveSupport's slice as well:

Quote.new(invoice.attributes.slice(*Quote.attribute_names))

Answer 3

sample_plan = Plan.last  # it contains object we want to convert
new_plan = Addon.new(sample_plan.attributes.except(:id)) # remove that particular column which is not common else you can get attribute errors.
new_plan # you can get the copy object with data in new one.

Answer 4

The straightforward way is something like this:

source = invoice.attributes
target = (source.keys & Quote.attribute_names).inject({}) {|target, key| target[key] = source[key]; target }
quote = Quote.new(target)