HackerRank Ruby Enumerable collect Solution

Hello coders, In this post, you will learn how to solve HackerRank Ruby Enumerable collect Solution. This problem is a part of the Ruby Tutorial series. One more thing to add, don’t straight away look for the solutions, first try to solve the problems by yourself. If you find any difficulty after trying several times, then look for the solutions.

HackerRank Ruby Enumerable collect

Let’s get started with HackerRank Ruby Enumerable collect Solution

Problem Statement

Beside simple methods to iterate over objects, Ruby Enumerable provides a number of important higher order constructs that we shall explore in further challenges. One of such important methods is collect method, also known as map.

map as the name may suggest, takes a function and maps (applies) it to a collection of values one by one and returns the collection of result.

That is,

map(f(x), [x1, x2, x3, . . . , xn]) -> [f(x1), f(x2), . . . , f(xn)]

This single powerful method helps us to operate on a large number of values at once.

For example,

>>> [1,2,3].map { |x| 2*x }
=> [2, 4, 6]
>>> {:a=>1, :b=>2, :c=>3}.collect { |key, value| 2*value }
=> [2, 4, 6]

Note that these methods are different from each in the respect that these methods return a new collection while former returns the original collection, irrespective of whatever happens inside the block.

In this challenge, your task is to write a method which takes an array of strings (containing secret enemy message bits!) and decodes its elements using ROT13 cipher system; returning an array containing the final messages.

For example, this is how ROT13 algorithm works,

Original text:

Why did the chicken cross the road?
Gb trg gb gur bgure fvqr!

On application of ROT13,

Jul qvq gur puvpxra pebff gur ebnq?
To get to the other side!

HackerRank Ruby Enumerable collect Solution

def rot13(secret_messages)
    # your code here
    input = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz'
    output = 'NOPQRSTUVWXYZABCDEFGHIJKLMnopqrstuvwxyzabcdefghijklm'
    secret_messages.collect { |str| str.tr(input, output)}
end

Note: This problem (Ruby Enumerable collect) is generated by HackerRank but the solution is provided by Chase2Learn. This tutorial is only for Educational and Learning purpose.