(Ruby) How do you check whether a range contains a subset of another range?

Question

If I have two ranges that overlap:

x = 1..10
y = 5..15

When I say:

puts x.include? y 

the output is:

Answer 1

Some helpful enumerable methods:

# x is a 'subset' of y
x.all?{|n| y.include? n}
# x and y overlap
x.any?{|n| y.include? n}
# x and y do not overlap
x.none?{|n| y.include? n}
# x and y overlap one time
x.one?{|n| y.include? n}

Answer 2

But if I want it to be "true" when there is partial overlap between two ranges, how would I write that?

You can convert the ranges to an array, and use the & operator (conjunction). This returns a new array with all the elements occuring in both arrays. If the resulting array is not empty, that means, that there are some overlapping elements:

def overlap?(range_1, range_2)
  !(range_1.to_a & range_2.to_a).empty?
end

Answer 3

Rails has Range#overlaps?

def overlaps?(other)
  cover?(other.first) || other.cover?(first)
end

Answer 4

Be careful using this with large ranges but this is an elegant way to do it:

(x.to_a & y.to_a).empty?