erb layout variables are undefined and not nil

Question

What I want to do is something like variable || "default string" variable || "default string" .

But this works only if variable is nil and for some reason it's undefined.

Is it possible to set the default value to nil, or is there a better way to achieve this?

Answer 1

您可以利用Ruby局部变量默认为nil的事实来获利：

variable ||= 'default string'

Answer 2

您可以这样做：

defined?(variable) ? variable : "default string"