Quack | A Quaver multihack

My issue is that I can't get the total amount of animals from my animals.txt file

I was looking for the canonical implementation of MergeSort on Haskell to port to HOVM, and I found this StackOverflow answer. When porting the algorithm, I realized something looked silly: the algorithm has a "halve" function that does nothing but split a list in two, using half of the length, before recursing and merging. So I thought: why not make a better use of this pass, and use a pivot, to make each half respectively smaller and bigger than that pivot? That would increase the odds that recursive merge calls are applied to already-sorted lists, which might speed up the algorithm!

I've done this change, resulting in the following code:

I have simple parent class named fruits and several childs, like this:

Parent:

I am trying to create a new array where elements of the original array are replaced with their corresponding values in the hash. I want to compare every element in arr to the key in hash and if they are equal shovel them into the arr and return it at the end. Why is my code not working and how can I access/return the key value of the respective entry in hash, not only the value pointed to by the key? If you get what I am saying.

Here is the code I am working with:

Here is the code I have so far

Using switch() in R, how can I abort with error if the input to EXPR is not defined inside the switch statement?

For example, consider the following function animal_sound(). It accepts an animal name and returns the sound the animal makes.

Let's say you have a lot of named index levels -- I'll show 4 here but use your imagination: