如果不止一个，我怎么能获得最后一个？

Question

In rails I have this:

page_classes.split(/\s/).last

Sometimes page_classes doesn't contain any whitespace and I get the error:

undefined method `last' for nil:NilClass

How can I get the last unless there is only one?

Answer 1

尝试这个

page_classes.split(/\s/).try(:last)

Answer 2

The problem is about your page_classes object.

page_classes.split("\s").last

Calling .last will ALWAYS work with an array (even empty). If you have probems, it means your page_classes object is nil or not a string that can be processed by split() .