如何在Ruby中檢查數組元素是否爲空？

Question

如何在Ruby中檢查數組元素是否爲空？

passwd.where { user =~ /.*/ }.uids 
=> ["0", "108", "109", "110", "111", "112", "994", "995", "1001", "1002", "", "65534"] 

Answer 1

要檢查，如果數組有一個空元素，的很多方法可以做到這一個是：

arr.any?(&:blank?) 

Answer 2

不知道你想要什麼用它做，但也有相當多的這種貓的皮膚的方法。更多信息將有助於縮小它的一些...

["0", "108", "109", "110", "111", "112", "994", "995", "1001", "1002", "", "65534"].map { |v| v.empty? } 
=> [false, false, false, false, false, false, false, false, false, false, true, false] 

["0", "108", "109", "110", "111", "112", "994", "995", "1001", "1002", "", "65534"].each_with_index { |v,i| puts i if v.empty? } 
10 

Answer 3

這些測試的空虛：

'foo'.empty? # => false 
''.empty? # => true 

[1].empty? # => false 
[].empty? # => true 

{a:1}.empty? # => false 
{}.empty? # => true 

測試，看是否在數組中的元素爲空，將使用類似的測試：

['foo', '', [], {}].select { |i| i.empty? } # => ["", [], {}] 
['foo', '', [], {}].reject { |i| i.empty? } # => ["foo"] 

，或者使用速記：

['foo', '', [], {}].select(&:empty?) # => ["", [], {}] 
['foo', '', [], {}].reject(&:empty?) # => ["foo"] 

Answer 4

arr = [ "0", "108", "", [], {}, nil, 2..1, 109, 3.2, :'' ] 

arr.select { |e| e.respond_to?(:empty?) && e.empty? } 
    #=> ["", [], {}, :""]