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"]

有什么办法像compact ，将做到没有循环？

有很多方法可以做到这一点，一个是reject

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

你也可以使用reject! ，这将修改cities 。如果拒绝，它将返回cities作为回报价值;如果不拒绝，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）。

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

在我的项目中，我使用delete ：

 cities.delete("")

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无元素。

这是对我有用的东西：

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

输出：

 [1, 2, "hello"]

 cities.delete_if(&:blank?)

这将删除nil值和空string（ "" ）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"] - [""]

使用reject ：

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

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

你想使用blank?的原因blank? 过empty? 是空白识别零，空string和空格。例如：

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

仍然会返回：

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

并呼吁empty? 上" "将返回false ，你可能希望是true 。

注意： blank? 只能通过Rails访问，Ruby只支持empty? 。

已经有很多答案，但是如果你在Rails世界里，这是另一种方法：

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

这是另一种方法来实现这一点

我们可以使用presence与select

 cities = ["Kathmandu", "Pokhara", "", "Dharan", nil, "Butwal"] cities.select(&:presence) ["Kathmandu", "Pokhara", "Dharan", "Butwal"]

如果你的数组中有混合types，这里是一个解决scheme：

 [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]

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

你可以试试这个

  cities.reject!(&:empty?)

最短路线cities.select(&:present?)

更新与严格的join和split

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

结果将是：

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