[英]erb layout variables are undefined and not nil
What I want to do is something like variable || "default string"
我想做的是类似
variable || "default string"
事情。 variable || "default string"
. variable || "default string"
。
But this works only if variable
is nil and for some reason it's undefined. 但这仅在
variable
为nil且由于某种原因未定义时才有效。
Is it possible to set the default value to nil, or is there a better way to achieve this? 可以将默认值设置为nil,还是有更好的方法来实现呢?
您可以利用Ruby局部变量默认为nil
的事实来获利:
variable ||= 'default string'
您可以这样做:
defined?(variable) ? variable : "default string"
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