Ruby 是Rails方法。如果空字符串之间有空格怎么办？@StevenaGuillar空格被视为长度1（因为空格是字符）。“”。空白？=>False我更喜欢使用.reject（&:blank？）来避免将nil值作为well@RanGaliliblank？是一个不错

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是Rails方法。如果空字符串之间有空格怎么办？@StevenaGuillar空格被视为长度1（因为空格是字符）。“”。空白？=>False我更喜欢使用.reject（&:blank？）来避免将nil值作为well@RanGalili

blank？

是一个不错的选择，但它是一个

rails

方法，这个问题是关于普通的

ruby

看起来非常危险！如果你有像“纽约”或“Naujoji Akmene”这样的城市，这肯定会失败：）在Ruby 2.3.1上，我得到了NoMethodError:“未定义的方法`blank？'for 1:Fixnum”试图执行它。@Tom blank？是一种特定于Rails的方法。普通ruby的数组中不存在。你要用空的吗？或者编写您自己的方法。@jpgeek感谢您的澄清，这就是我在实现

：blank时遇到的问题？

是Rails特定的。因为

NoMethodError:undefined method empty？对于nil:NilClass

，

：空白

优于

：empty？

：blank

优于

：empty

。因为

：empty

不适用于

nil

['a'，nil'，b'，''。选择（&:present？）

进行速记

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

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

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

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

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

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

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

cities.delete("")

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

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

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

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

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

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

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

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

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

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

[1, 2, "hello"]

 cities.reject!(&:empty?)

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

cities.select(&:presence)

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

cities.delete_if(&:blank?)

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

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

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

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

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

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

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

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

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