Question

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"]

有没有类似compact的方法可以在没有循环的情况下执行此操作？

Answer 1

有很多方法可以做到这一点，一个是reject

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

您还可以使用reject!，这将修改cities。如果它拒绝某些内容，它将返回cities作为其返回值，如果没有拒绝则返回nil。如果你不小心，这可能是一个问题（感谢ninja08在评论中指出这一点）。

Answer 2

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

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

Answer 3

这对我有用：

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

输出：

[1, 2, "hello"]

Answer 4

在我的项目中，我使用delete：

cities.delete("")

Answer 5

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。

Answer 6

最明确的

cities.delete_if(&:blank?)

这将删除nil值和空字符串（""）值。

例如：

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

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

Answer 7

试试这个：

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

Answer 8

使用reject：

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

Answer 9

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

您希望blank?使用empty?的原因是空白识别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"]

在empty?上调用" "将返回false，您可能想要true。

注意：blank?只能通过Rails访问，Ruby只支持empty?。

Answer 10

已经有很多答案，但如果您在Rails世界中，这是另一种方法：

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

Answer 11

这是实现此目的的另一种方法

我们可以将ID与presence

一起使用

select

Answer 12

如果你的数组中有混合类型，这是一个解决方案：

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

解决方案：

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

输出：

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

Answer 13

你可以试试这个

 cities.reject!(&:empty?)

Answer 14

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

Answer 15

compact_blank（Rails 6.1 +）

如果您使用的是Rails（或独立的ActiveSupport），则从版本6.1开始，有一种compact_blank方法将从其中删除blank值数组。

它使用引擎盖下的Object#blank?来确定某项是否为空白。

["Kathmandu", "Pokhara", "", "Dharan", nil, "Butwal"].compact_blank
# => ["Kathmandu", "Pokhara", "Dharan", "Butwal"]

[1, "", nil, 2, " ", [], {}, false, true].compact_blank
# => [1, 2, true]

这里是link to the docs和link to the relative PR。

也提供破坏性的变体。参见Array#compact_blank!。

如果您只需要删除nil个值，

请考虑使用Ruby内置Array#compact和Array#compact!方法。

["a", nil, "b", nil, "c", nil].compact
# => ["a", "b", "c"]

Answer 16

要删除nil值，请执行以下操作：

 ['a', nil, 'b'].compact  ## o/p =>  ["a", "b"]

要删除空字符串：

   ['a', 'b', ''].select{ |a| !a.empty? } ## o/p => ["a", "b"]

要同时删除nil和空字符串：

['a', nil, 'b', ''].select{ |a| a.present? }  ## o/p => ["a", "b"]

Answer 17

最短路[{1}}

Answer 18

另一种方法：

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

Answer 19

普通的红宝石：

values = [1,2,3, " ", "", "", nil] - ["", " ", nil]
puts values # [1,2,3]

Answer 20

严格更新join＆amp; split

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

结果将是：

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

请注意：这不适用于带空格的城市

如何从数组中删除空白元素？

20 个答案:

最明确的

compact_blank（Rails 6.1 +）