三元条件更好

Question

方法find_something可能返回nil。在以下代码中，

something = find_something(id) ? find_something(id) : create_something(foo)

find_something(id)被调用两次。我想避免这种气味。有没有办法避免此表达式中的冗余？

Answer 1

这样的事吗？

something = find_something(id) || create_something(foo)

Answer 2

There's not quite enough detail given to say this with confidence, though it might be this is a case for find_or_create_by.

If this does suit, you would just do:

something = YourModel.find_or_create_by(id: id)

You can also provide a block to this, which is passed to the create method if no record is found. For example:

something = YourModel.find_or_create_by(id: id) do |instance|
  # this block only gets executed on create
  instance.some_new_attribute = 'goes here'
end

Hope that's useful - let me know if it suits your use case.