我有下面的数组
cities = ["Kathmandu", "Pokhara", "", "Dharan", "Butwal"]
我想从数组中删除空白元素，并希望得到以下结果:
cities = ["Kathmandu", "Pokhara", "Dharan", "Butwal"]
有没有像compact这样不需要循环的方法?
当前回答
当我想整理一个这样的数组时，我使用:
["Kathmandu", "Pokhara", "", "Dharan", "Butwal"] - ["", nil]
这将删除所有空白或nil元素。
其他回答
有很多方法可以做到这一点，其中之一是拒绝
noEmptyCities = cities.reject { |c| c.empty? }
你也可以用reject!，这将改变城市的位置。如果拒绝某项，它将返回cities作为返回值，如果没有拒绝，则返回nil。如果你不小心，这可能是一个陷阱(感谢ninja08在评论中指出这一点)。
使用拒绝:
>> cities = ["Kathmandu", "Pokhara", "", "Dharan", "Butwal"].reject{ |e| e.empty? }
=> ["Kathmandu", "Pokhara", "Dharan", "Butwal"]
另一种方法:
> ["a","b","c","","","f","g"].keep_if{|some| some.present?}
=> ["a","b","c","f","g"]
在我的项目中，我使用delete:
cities.delete("")
cities.reject! { |c| c.blank? }
为什么要用空白?在空的吗?blank可以识别nil，空字符串和空白。例如:
cities = ["Kathmandu", "Pokhara", " ", nil, "", "Dharan", "Butwal"].reject { |c| c.blank? }
仍然会返回:
["Kathmandu", "Pokhara", "Dharan", "Butwal"]
叫空?On " "将返回false，您可能希望它为true。
注:空白?只能通过Rails访问，Ruby只支持空?
