Ruby Set Intersection

Here we will discuss the basic set operations i e union intersection and difference.

Ruby set intersection.

Like other languages ruby also provides a set class that represents the mathematical notion of a set. 2 3 this gives you the elements common in both sets. These 3 operators union difference intersection can also be used with arrays. Def intersect var x multiset new end here is an example.

And here s the set intersection operator. Set implements a collection of unordered values with no duplicates. Returns a new array. Ruby array intersection operation last updated.

Intersect two arrays returning values that occur in both of them as a set an array with distinct values. Array is a array class method which performs set intersection operation on the arrays. 2 ruby core 89287 updated by c4am95 travis hunter almost 2 years ago. A superset is a set that contains all the elements of another set.

X 1 1 2 4 y 1 2 2 2 then the intersection of x and y is 1 2. Set intersection in ruby. Arrays for performing the intersection operation. Common elements from both the arrays.

Additional speedup comes from using each instead of do with enum. In the first form if no arguments are sent the new array will be empty. The set is an unordered collection with no duplicate items. This is a hybrid of array s intuitive inter operation facilities and hash s fast lookup.

Current implementation computes set intersection s1 s2 in o s2 size time. It can be reduced to o s1 size s2 size min time. For intersection and union my code starts like this. Check which pieces of equipment iron man has from a fixed list.

I will cover arrays first because this is one of the most common objects found. The syntax is similar in both so don t worry about having to learn lots of different things. There are a couple of ways you can do intersections in ruby ruby i will talk you through both of them. The second form creates a copy of the array passed as a parameter the array is generated by calling to ary on the parameter.

You can check if one set is a superset of. If you have zero interest to the intersection itself i think you can avoid creating the temporary array. Set is easy to use with enumerable objects implementing each most of the initializer methods and binary operators accept generic enumerable objects besides sets and arrays. I have all the required methods but i m unsure of how to write intersection union and subset methods.

When a size and an optional default are sent an array is created with size copies of default take notice that all elements will reference the same object default. Set new 1 3 set new 2 5 set.