What is Functional Programming?

Functional Programming is a programming paradigm that utilizes functions for clean, consistent and maintainable code. It uses a different paradigm or approach compared to other programming paradigms such as the object-oriented programming. Functional programming utilizes functions to achieve results which makes it effective and a very good option for processing large amounts of data at high speed.

Now, what are functions? A Function performs a sequence of actions. It takes an input, processes it and then produces an output. There are two types of functions. We have the pure function and the traditional function. Pure functions will always do the same things and return the same results no matter how many times you call them. One difference between pure and traditional functions is that traditional functions can access and modify variables on global state while pure functions cannot. On the other hand though, both traditional and pure functions can access variables on the local state.

You may wonder though? How does the use or utilization of functions in functional programming make codes cleaner and consistent? This is so because functions are considered standalone or independent which aids or makes way for the elegant nature of the code. One very important thing to note about functional programming is that it does not change the data outside the scope of the function meaning that the function should avoid modifying the input data or arguments being passed. Functional programming is quite effective actually and the great thing about it is that there are functions that are already built in for you which as a developer, you can use multiple times and can also save you a lot of development time. In addition to the built in functions, you can also create your own functions specifically for your code. Now, lets learn more about pure functions.

What is a pure function? A pure function is a function that does not change or have any effect on a variable, data list or sets beyond its own scope. Lets take a look at this example, lets say you declare a list in the global scope, now to explain the limit of a pure function, a pure function declared after that list cannot add something to that list or alter it in anyway. Pure functions are very beneficial for developers in a number of ways. Firstly, with pure functions, you always know what the outcome will be based on the fact that pure functions are consistent snippets of code that do exactly what they are intended to do and secondly, they also help prevent changes on the global scope ensuring data stays reliable. Yes, making use of pure functions will help keep your code cleaner, easier to debug, easier to extend and easier to understand.

Another important aspect of functional programming is recursion. Recursion simply refers to a function that calls itself, creating a pattern of repeating itself over and over and over. It is an important concept in coding as it is used to solve problems that can be broken down into smaller repetitive problems. When a problem is too complex for an iterative approach, a recursive function is used. Always note though that when coding a recursive function, you must always consider the results, if you don’t, it will spin into an infinite loop and will eventually suck up all the memory until the program eventually crashes or gets terminated. In conclusion, making use of a recursive function is wise as a developer as it helps to make your work neater and less bulky and complex tasks can be broken down or dissolved into smaller problems.

As a developer, you will be tested from time to time on your skills and knowledge in the field of tech. As a Python developer, one of the basic ways to test your problem solving skills is by testing your knowledge on how to reverse a string as it is very useful in production environment.

Therefore, how can we reverse a string in Python?

Python unlike some programming languages do not have a built in function to reverse a string, but due to its flexibility, it does have several functions that can be used to reverse a string. The first is with the slice function. To use a slice function, you have to write the format of a slice function first, it always start with the name of a string(str), then an equal too operator(=) followed by an open square bracket, then the start parameter(start) followed by a colon(:), then the stop parameter(stop) followed by a colon(:), then lastly the step parameter(step) followed by a closed square bracket and then add an # symbol in front of the line to indicate its a note. This is called the extended slice syntax. It should look like this:

# str = [start:stop:step]

The start and stop parameters are the indices between which the function manipulates the string while the step parameter is the hops or jumps. So to reverse a string in Python, the first thing to do is to declare the string and the word you want to reverse, then on a new line, you declare another variable with the value being the name of the variable your string is assigned to but this time with a slice function. To instruct Python to use the entire string, you have to leave the value of the stop and start parameter empty but as for the step parameter, you give it a value of -1. The negative value indicates that the string needs to be reversed from the right one index position at a time and then on printing out your code, your string is reversed. The slice function is actually the simplest way to reverse a string in Python. Here is a more detailed example of how to reverse a string using the slice function:

# str = [start:stop:step]

trial = “reverse”

new_trial = trial[::-1]

print(new_trial)

The other way to reverse a string in Python is using a slice function with recursion meaning using a recursive function and implementing the slice function within.

Lastly, we have the map and filter function. They are also important functions in functional programming. The map and filter function is a high order function that accepts another function and a list or sequence of iterables as parameters and then provides a result or output after successfully applying the function to each iterable in a sequence. The difference between the two is that a map function takes all object in the list and allows you to apply a function to it while a filter also does the same but it creates a new list and only return values where the evaluated function returns true.

Conclusion

In conclusion, functions make our lives as developers easier, from the various built in functions to functions that can be created by us personally. They all help to make our codes easier to understand and cleaner. Therefore, make it a goal as a developer to work smarter and neater with functional programming.