A Beginners Guide to Scala, Object Orientation and Functional Programming


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Scala Program Example

Yes, it can. Be sure to do performance testing in your own app. If you need a performance boost, then consider using Immutable. This is the same technique used internally by functional programming languages such as Clojure and Scala. Remember thinking, "When am I ever going to use this? There are libraries such as Ramda and lodash that provide a more elegant way of composing functions.

Instead of simply passing the return value from one function to the next, we can treat function composition in the more mathematical sense. We can create a single composite function made up from the others i. Okay, so we can do function composition in JavaScript. What's the big deal? Well, if you're really onboard with functional programming, then ideally your entire program will be nothing but function composition. There will be no loops for , for None period. But that's impossible, you say!

A Beginner's Guide to Scala, Object Orientation and Functional Programming

Not so. That leads us to the next two topics: recursion and higher-order functions. Let's say that you would like to implement a function that computes the factorial of a number. Let's recall the definition of factorial from mathematics:. That is, n! We can write a loop that computes that for us easily enough. Notice that both product and i are repeatedly being reassigned inside the loop.

Beginners Guide to Functional Programming: Part 1

This is a standard procedural approach to solving the problem. How would we solve it using a functional approach? We would need to eliminate the loop and make sure we have no variables being reassigned. Recursion is one of the most powerful tools in the functional programmer's toolbelt. Recursion asks us to break down the overall problem into sub-problems that resemble the overall problem. Computing the factorial is a perfect example. To compute n! That's the same thing as saying:. We found a sub-problem to solve n-1! There's one more thing to take care of: the base case.

The base case tells us when to stop the recursion. If we didn't have a base case, then recursion would go on forever. In practice, you'll get a stack overflow error if there are too many recursive calls. What is the base case for the factorial function?

Beginner's guide to functional programming in JavaScript | jerksibpionanlo.ga

With this information in mind, let's write a recursive factorial function. Okay, so let's compute recursiveFactorial , because When we do, we get this:. So what's going on here? We got a stack overflow error! It's not because of infinite recursion. We know that we handled the base case i. It's because the browser has a finite stack and we have exceeded it.


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Each call to recursiveFactorial causes a new frame to be put on the stack. We can visualize the stack as a set of boxes stacked on top of each other. Each time recursiveFactorial gets called, a new box is added to the top. The following diagram shows a stylized version of what the stack might look like when computing recursiveFactorial 3. Note that in a real stack, the frame on top would store the memory address of where it should return after executing, but I have chosen to depict the return value using the variable r.

I did this because JavaScript developers don't normally need to think about memory addresses. Is there anything we can do about that? It turns out that, yes, there is something we can do about it. As part of the ES aka ES6 specification, an optimization was added to address this issue. It's called the proper tail calls optimization PTC. It allows the browser to elide, or omit, stack frames if the last thing that the recursive function does is call itself and return the result. Actually, the optimization works for mutually recursive functions as well, but for simplicity we're just going to focus on a single recursive function.

You'll notice in the stack above that after the recursive function call, there is still an additional computation to be made i. That means that the browser cannot optimize it using PTC; however, we can rewrite the function in such a way so that the last step is the recursive call. One trick to doing that is to pass the intermediate result in this case the product into the function as an argument.

Let's visualize the optimized stack now when computing factorial 3. As the following diagram shows, in this case the stack never grows beyond two frames. The reason is that we are passing all necessary information i.

So, after the product has been updated, the browser can throw out that stack frame. You'll notice in this diagram that each time the top frame falls down and becomes the bottom frame, the previous bottom frame gets thrown out. It's no longer needed. The optimized stack for recursively calculating 3! Now run that in a browser of your choice, and assuming that you ran it in Safari, then you will get the answer, which is Infinity it's a number higher than the maximum representable number in JavaScript.

Other resources

But we didn't get a stack overflow error, so that's good! Now what about all the other browsers? Then, as an important step, you will install pyspark and findspark since spylon-kernel also installs some spark components. Finally, start your jupyter notebook and choose kernel as spylon-kernel and you are good to go! So as you can observe from the above output, you were successful in configuring the Scala environment in jupyter notebook. As you can see, it was so simple, just a print command followed by the input as an argument. Scala is case-sensitive , which means identifier DataCamp and dataCamp would have a different meaning in Scala.

In Scala, all class names first letter should be in Upper Case. If many words are combined to form a name of the class, each separate word's first letter should be in Upper Case.

What is Scala?

The method names in Scala work slightly differently as compared to class names mainly to distinguish the method names from class names. The method names should start with a Lower Case letter Source. If multiple words are combined to form the name of the method, then each inner word's first letter should be in Upper Case.


  1. Strongly Correlated Magnetic and Superconducting Systems: Proceedings of the El Escorial Summer School Held in Madrid, Spain, 15–19 July 1996.
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  5. Introduction | Tour of Scala | Scala Documentation;
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  8. For example, def firstDatacampScalaTutorial. In Scala, the name of the program file should exactly match the object name. When saving the file, you need to save it using the object name and append.

    A Beginners Guide to Scala, Object Orientation and Functional Programming A Beginners Guide to Scala, Object Orientation and Functional Programming
    A Beginners Guide to Scala, Object Orientation and Functional Programming A Beginners Guide to Scala, Object Orientation and Functional Programming
    A Beginners Guide to Scala, Object Orientation and Functional Programming A Beginners Guide to Scala, Object Orientation and Functional Programming
    A Beginners Guide to Scala, Object Orientation and Functional Programming A Beginners Guide to Scala, Object Orientation and Functional Programming
    A Beginners Guide to Scala, Object Orientation and Functional Programming A Beginners Guide to Scala, Object Orientation and Functional Programming
    A Beginners Guide to Scala, Object Orientation and Functional Programming A Beginners Guide to Scala, Object Orientation and Functional Programming
    A Beginners Guide to Scala, Object Orientation and Functional Programming A Beginners Guide to Scala, Object Orientation and Functional Programming
    A Beginners Guide to Scala, Object Orientation and Functional Programming A Beginners Guide to Scala, Object Orientation and Functional Programming
    A Beginners Guide to Scala, Object Orientation and Functional Programming

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