Ruby-on-rails 如何为 nil:NilClass 错误修复未定义的方法“split”？
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How to fix undefined method `split' for nil:NilClass error?
提问by sharataka
I have the following line in my Rails app:
我的 Rails 应用程序中有以下行：
@images = @product.secondary_images.split(",")
When @product.secondary_images has content in it, this runs fine. However, when there is no content, I get this error:
当@product.secondary_images 中有内容时，它运行良好。但是，当没有内容时，我收到此错误：
undefined method `split' for nil:NilClass
How can I assign another value to @images if there is no content in it?
如果 @images 中没有内容，我如何为它分配另一个值？
回答by pduersteler
A possible solution would be to use trywhich does return nil in case your method cannot be sent to secondary_images. And then use the OR-operator to assign something else.
一个可能的解决方案是使用trywhich 确实返回 nil 以防您的方法无法发送到secondary_images. 然后使用 OR 运算符分配其他内容。
@images = @product.secondary_images.try(:split, ",") ||?'some other value'
回答by Kuf
回答by omarvelous
You can use trymethod
你可以使用try方法
nil.try(:split, ",")
回答by Christopher WJ Rueber
Generally subjective answer, but I'd probably handle it this way myself, if I wanted it all in one line:
通常是主观的答案，但如果我想在一行中全部解决，我可能会自己这样处理：
@images = @product.secondary_images.nil? ? 'another value' : @product.secondary_images.split(',')
