I have two arrays of numbers that have the same size. How can I tell if there is any element in the second array that is greater than the first array at a given index? With this example:
a = [2, 8, 10]
b = [3, 7, 5]
3 is greater than 2 at position 0. But in the following:
a = [1, 10]
b = [0, 8]
there is no such element. At index 0, 0 is not greater than 1, and at index 1, 8 is not greater than 10.
Try this one
a.each_with_index.any? { |item, index| b[index] > item }
a.each_index.any? { |index| b[index] > a[index] }?
No need for indices. Just pair them and check each pair.
b.zip(a).any? { |x, y| x > y }
=> true or false
And a tricky one: Check whether at every position, a is the maximum:
a.zip(b).map(&:max) != a
=> true or false
And a very efficient one (both time and space):
b.zip(a) { |x, y| break true if x > y }
=> true or nil
(If you need true/false (often you don't, for example in if-conditions), you could prepend !! or append || false)
.lazy in there :-)
b.lazy.zip(a).any? { |x, y| x > y } would be likely a bit better, yes..lazy just unnecessarily clutters the code and makes it slower. Anyway... I just added another solution that's very efficient in both time and space.If there's a number in b greater than the number in a at the given index, this will return the number in b. If no numbers in b are greater, nil will be returned.
b.detect.with_index { |n, index| n > a[index] }
For example, if you have the following arrays.
a = [3, 4, 5]
b = [6, 7, 8]
You'll get a return value of 6.
