rails - Finding intersections between multiple arrays

ruby-on-rails ruby arrays array-intersect
Alex picture Alex · Jul 7, 2010 · Viewed 34.4k times · Source

I am trying to find the intersection values between multiple arrays.

for example

code1 = [1,2,3]
code2 = [2,3,4]
code3 = [0,2,6]

So the result would be 2

I know in PHP you can do this with array_intersect

I wanted to be able to easily add additional array so I don't really want to use multiple loops

Any ideas ?

Thanks, Alex

Answer

Anurag picture Anurag · Jul 7, 2010

Use the & method of Array which is for set intersection.

For example:

> [1,2,3] & [2,3,4] & [0,2,6]
=> [2]

Related questions

Remove duplicate elements from array in Ruby

I have a Ruby array which contains duplicate elements. array = [1,2,2,1,4,4,5,6,7,8,5,6] How can I remove all the duplicate elements from this array while retaining all unique elements without using for-loops and iteration?

Read More
How to determine if one array contains all elements of another array

Given: a1 = [5, 1, 6, 14, 2, 8] I would like to determine if it contains all elements of: a2 = [2, 6, 15] In this case the result is false. Are there any built-in Ruby/Rails methods to identify such array inclusion? One way to implement this is: a2.…

Read More
How do I pass multiple arguments to a ruby method as an array?

I have a method in a rails helper file like this def table_for(collection, *args) options = args.extract_options! ... end and I want to be able to call this method like this args = [:name, :description, :start_date, :end_date] …

Read More