如何从数组中删除空白元素？

我有以下数组

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"]

有没有这样的方法compact可以做到没有循环？

有很多方法可以做到这一点，一种是 reject

noEmptyCities = cities.reject { |c| c.empty? }

您也可以使用reject!，它将cities在适当位置进行修改。它要么返回cities作为它的返回值，如果它拒绝的东西，或者nil如果没有拒绝制成。如果您不小心的话，这可能是一个陷阱（感谢ninja08在评论中指出了这一点）。

1.9.3p194 :001 > ["", "A", "B", "C", ""].reject(&:empty?)

=> ["A", "B", "C"]

这对我有用：

[1, "", 2, "hello", nil].reject(&:blank?)

输出：

[1, 2, "hello"]

在我的项目中，我使用delete：

cities.delete("")

当我想整理这样的数组时，我使用：

["Kathmandu", "Pokhara", "", "Dharan", "Butwal"] - ["", nil]

这将删除所有空白或零元素。

最明确的

cities.delete_if(&:blank?)

这将同时删除nil值和空字符串（""）值。

例如：

cities = ["Kathmandu", "Pokhara", "", "Dharan", "Butwal", nil]

cities.delete_if(&:blank?)
# => ["Kathmandu", "Pokhara", "Dharan", "Butwal"]

尝试这个：

puts ["Kathmandu", "Pokhara", "", "Dharan", "Butwal"] - [""]

用途reject：

>> cities = ["Kathmandu", "Pokhara", "", "Dharan", "Butwal"].reject{ |e| e.empty? }
=> ["Kathmandu", "Pokhara", "Dharan", "Butwal"]

cities.reject! { |c| c.blank? }

您要使用blank?over 的原因empty?是，空格可以识别nil，空字符串和空格。例如：

cities = ["Kathmandu", "Pokhara", " ", nil, "", "Dharan", "Butwal"].reject { |c| c.blank? }

仍会返回：

["Kathmandu", "Pokhara", "Dharan", "Butwal"]

并呼吁empty?对" "将返回false，这你可能想true。

注意：blank?仅可通过Rails访问，Ruby仅支持empty?。

已经有了很多答案，但是如果您在Rails世界中，这是另一种方法：

 cities = ["Kathmandu", "Pokhara", "", "Dharan", "Butwal"].select &:present?

这是实现此目的的另一种方法

我们可以使用presence与select

cities = ["Kathmandu", "Pokhara", "", "Dharan", nil, "Butwal"]

cities.select(&:presence)

["Kathmandu", "Pokhara", "Dharan", "Butwal"]

如果您的数组中有混合类型，这是一个解决方案：

[nil,"some string here","",4,3,2]

解：

[nil,"some string here","",4,3,2].compact.reject{|r| r.empty? if r.class == String}

输出：

=> ["some string here", 4, 3, 2]

你可以试试看

 cities.reject!(&:empty?)

 cities = ["Kathmandu", "Pokhara", "", "Dharan", "Butwal"].delete_if {|c| c.empty? } 

最短的方法 cities.select(&:present?)

另一种方法：

> ["a","b","c","","","f","g"].keep_if{|some| some.present?}
=> ["a","b","c","f","g"]

用join＆严格更新split

cities = ["Kathmandu", "Pokhara", "", "Dharan", "Butwal"]
cities.join(' ').split

结果将是：

["Kathmandu", "Pokhara", "Dharan", "Butwal"]

请注意：这不适用于有空间的城市