CODEWITHSUNDEEP
arraysruby
user7055375
user7055375

Reputation:

Compare an element from one array with an element from another array

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.

Upvotes: 0

Views: 862

Answers (3)

Stefan Pochmann
Stefan Pochmann

Reputation: 28596

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)

Upvotes: 5

Derek Hopper
Derek Hopper

Reputation: 2258

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.

Upvotes: 0

Ursus
Ursus

Reputation: 30056

Try this one

a.each_with_index.any? { |item, index| b[index] > item }

Upvotes: 5

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