I am new to Ruby and stuck with this issue. Let's say I have an array like this:
arr = [1, 2, 's', nil, '', 'd']
and I want to remove nil and blank string from it, i.e. final array should be:
arr = [1, 2, 's', 'd']
I tried compact but it gives this:
arr.compact!
arr #=> [1, 2, 's', '', 'd'] doesn't remove empty string.
I was wondering if there's a smart way of doing this in Ruby.
You could do this:
arr.reject { |e| e.to_s.empty? } #=> [1, 2, "s", "d"]
Note nil.to_s => ''.
arr.reject(&:blank?)
:blank?will only work in Rails as it is an ActiveSupport method and not a part of ruby.Since you want to remove both nil and empty strings, it's not a duplicate of How do I remove blank elements from an array?
You want to use .reject:
arr = [1, 2, 's', nil, '', 'd']
arr.reject { |item| item.nil? || item == '' }
NOTE: reject with and without bang behaves the same way as compact with and without bang: reject! and compact! modify the array itself while reject and compact return a copy of the array and leave the original intact.
If you're using Rails, you can also use blank?. It was specifically designed to work on nil, so the method call becomes:
arr.reject { |item| item.blank? }
empty?
arr.reject &:blank?.empty? instead of blank?If you are using Rails (or a standalone ActiveSupport), starting from version 6.1, there is a compact_blank method which removes blank values from arrays.
It uses Object#blank? under the hood for determining if an item is blank.
[1, 2, 's', nil, '', 'd'].compact_blank
# => [1, 2, 's', 'd']
[1, "", nil, 2, " ", [], {}, false, true].compact_blank
# => [1, 2, true]
Here is a link to the docs and a link to the relative PR.
A destructive variant is also available. See Array#compact_blank!.
arr.reject(&:blank?)
Just use this, no need to anything else.
blank isn't a Ruby method, it's a Rails one, so you should add the active_support needed library, and the question has tagged Ruby not Rails. Anyways, this answer states something pointed before.You can also use - to remove all nil and '' elements:
arr -= [nil, '']
#=> [1, 2, "s", "d"]
Or compact and reject with shortcut (in case you are not using Rails where you can just use arr.reject(&:blank?) ):
arr = arr.compact.reject(&''.method(:==))
#=> [1, 2, "s", "d"]
You can use compact with reject
arr = [1, 2, 's', nil, '', 'd']
arr = [1, 2, 's', 'd']
arr = arr.compact.reject { |h| h == "" }
or
arr = arr.compact.delete_if { |h| h == "" }
The simplest and fast way of doing this is :
arr = [1, 2, 's', nil, '', 'd'] - [nil,'']
==> arr = [1, 2, 's', 'd']
You can use compact and delete_if method to remove nil and blank string in an array in Ruby
arr = [1, 2, 's', nil, '', 'd']
arr.compact!.delete_if{|arrVal| arrVal.class == String and arrVal.empty?}
=> [1, 2, "s", "d"]
try this out:
[1, 2, "s", nil, "", "d"].compact.select{|i| !i.to_s.empty?}
reject, rather than select, bot to get rid of ! and because compact is also a form of rejection. To me, "reject this and reject that" reads better than "reject this and select that".Note: I am considering the array might have string with white spaces in it.
You can do:
arr = [1, 2, 's', nil, ' ', 'd']
arr.reject{|a| a.nil? || (a.to_s.gsub(' ', '') == '') }
#=> [1, 2, "s", "d"]
or:
arr.reject{|a| a.nil? || (a.to_s.gsub(' ', '').empty?) }
#=> [1, 2, "s", "d"]
or if you want to update arr object itself then:
arr.reject!{|a| a.nil? || (a.to_s.gsub(' ', '') == '') } # notice the ! mark, it'll update the object itself.
p arr #=> [1, 2, "s", "d"]
Hope this will work for your case :
arr = [1, 2, 's', nil, '', 'd']
arr.select{|x| x.to_s!="" }
I would probably add .strip to eliminate potential whitespace headaches (assuming its not a rails app).
array = [1, 2, "s", nil, " ", "d", "\n"]
array.reject!{|a| a.nil? || (a.to_s.strip.empty?) }
#=> [1, 2, "s", "d"]
blank?works but is not available in plain Ruby. It comes with Rails.