CODEWITHSUNDEEP
ruby
Gareth Burrows
Gareth Burrows

Reputation: 1182

remove items in 1 ruby array from another array

I have one array in rails, which for the sake of simplicity, we shall say is

@users = current_account.users

I have several other arrays, which contains subsets of that first array. These look like this

@missing_genders = @users.select{ |u| u.gender.nil?}
@missing_reference = @users.select{ |u| u.reference_number.nil?}

I have a few others like this too. What I need is to produce a list of all the users who are NOT erroneous. so basically everyone in the first array, who does not exist in any of the other arrays?

thinking through it, I have

@main_array = [1,2,3,4,5]
@error_array_1 = [1]
@error_array_2 = [1,2,3]

And I am looking to generate

@final_array = [4,5]

Upvotes: 0

Views: 112

Answers (2)

hirolau
hirolau

Reputation: 13901

This is the way to do it if you have many arrays:

main_array = [1,2,3,4,5,6]
error_array_1 = [1]
error_array_2 = [1,2,3]
error_array_4 = [6]

p [main_array,error_array_1,error_array_2,error_array_4].reduce(:-) #=> [4, 5]

Upvotes: 0

Grych
Grych

Reputation: 2901

The answer is really easy, you want to subtract the error_arrays from the main array, like this:

@final_array = @main_array - @error_array_1 - @error_array_2
=> [4, 5]

Upvotes: 4

Related Questions