How to remove a field from params[:something]

Question

My registration form, which is a form for the Users model, takes a string value for company. However, I have just made a change such that users belongs_to companies. Therefo

Answer 1

Rails 4/5 - edited answer (see comments)

Since this question was written newer versions of Rails have added the extract! and except eg:

new_params = params.except[the one I wish to remove]

This is a safer way to 'grab' all the params you need into a copy WITHOUT destroying the original passed in params (which is NOT a good thing to do as it will make debugging and maintenance of your code very hard over time).

Or you could just pass directly without copying eg:

@person.update(params[:person].except(:admin))

The extract! (has the ! bang operator) will modify the original so use with more care!

Original Answer

You can remove a key/value pair from a Hash using Hash#delete:

params.delete :company

If it's contained in params[:user], then you'd use this:

params[:user].delete :company