问题描述
我的注册表单是用户模型的表单，它采用公司的字符串值.但是，我刚刚进行了更改，使用户属于公司.因此，我需要将 Company 的对象传递给 Users 模型.
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. Therefore, I need to pass an object of Company to the Users model.
我想使用表单中的字符串值来获取 Company 的对象:
I want to use the string value from the form to obtain the an object of Company:
@user.company = Company.find_by_name(params[:company])
我相信上述方法有效，但是当我调用时，表单将 :company(它是字符串)传递到模型中:
I believe the above works, however the form is passing the :company (which is string) into the model when I call:
@user = User.new(params[:user])
因此，我想知道(并且找不到如何)在将 :company 参数传递给 User 模型之前删除它.
Therefore, I want to know (and cannot find how) to remove the :company param before passing it to the User model.
推荐答案
Rails 4/5 - 已编辑的答案(见评论)
自从编写这个问题以来，较新版本的 Rails 添加了 extract! 和 except 例如:
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]
这是一种更安全的方法，可以将您需要的所有参数抓取"到副本中，而不会破坏传入的原始参数(这不是一件好事，因为随着时间的推移，它会使代码的调试和维护变得非常困难).
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).
或者你可以直接通过而不复制，例如:
Or you could just pass directly without copying eg:
@person.update(params[:person].except(:admin))
extract!(有 !bang 操作符)会修改原来的，所以使用时要小心！
The extract! (has the ! bang operator) will modify the original so use with more care!
原答案
您可以使用 Hash#delete 从哈希中删除键/值对:
You can remove a key/value pair from a Hash using Hash#delete:
params.delete :company
如果它包含在 params[:user] 中，那么你会使用这个:
If it's contained in params[:user], then you'd use this:
params[:user].delete :company
这篇关于如何从 params[:something] 中删除一个字段的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！