Remove nil and blank string in an array in Ruby

Question

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.

Answer 1

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 == "" }

Answer 2

The simplest and fast way of doing this is :

arr = [1, 2, 's', nil, '', 'd'] - [nil,'']

==> arr = [1, 2, 's', 'd']

Answer 3

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"]

Answer 4

arr.reject(&:blank?)

Just use this, no need to anything else.

Answer 5

I tend to do:

arr = [1, 2, 's', nil, '', 'd']
arr.reject(&:blank?)

returns:

=> [1, 2, "s", "d"]

Answer 6

You can also use - to remove all nil and '' elements:

arr -= [nil, '']
#=> [1, 2, "s", "d"]

Demonstration

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"]

Demonstration