{"id":11482,"date":"2022-07-13T07:00:15","date_gmt":"2022-07-13T14:00:15","guid":{"rendered":"https:\/\/www.codingdojo.com\/blog\/?p=11482"},"modified":"2024-10-30T18:27:15","modified_gmt":"2024-10-31T01:27:15","slug":"what-is-functional-programming","status":"publish","type":"post","link":"https:\/\/www.codingdojo.com\/blog\/what-is-functional-programming","title":{"rendered":"What Is Functional Programming and Why Use It?"},"content":{"rendered":"\r\n

If you\u2019ve just started learning how to code<\/a>, deciding which programming paradigm and programming language to learn first<\/a> can be tricky.\u00a0\u00a0<\/p>\r\n\r\n\r\n\r\n

If you want to master a programming paradigm relevant to today\u2019s tech landscape, consider going with functional programming. It\u2019s a simplified, cleaner, and more predictable way to create code. Your resulting code is also easier to test and maintain.<\/p>\r\n\r\n\r\n\r\n

But what exactly is functional programming? Read on to learn more about this programming paradigm, its advantages, and the most popular functional programming languages.<\/p>\r\n\r\n\r\n\r\n

What Is Functional Programming?<\/h2>\r\n\r\n\r\n\r\n

Functional programming (FP) is an approach to software development that uses pure functions to create maintainable software. In other words, building programs by applying and composing functions.\u00a0<\/p>\r\n\r\n\r\n\r\n

Functional programming harnesses language support by using functions as variables, arguments, and return values\u2014creating elegant and clean code in the process. FP also uses immutable data and avoids concepts like shared states. This is in contrast to object-oriented programming (OOP), which uses mutable data and shared states.<\/p>\r\n\r\n\r\n\r\n

Functional programming languages focus on declarations and expressions rather than the execution of statements. Functions are also treated like first-class citizens\u2014meaning they can pass as arguments, return from other functions, and attach to names.<\/p>\r\n\r\n\r\n\r\n

FP focuses on the results, not the process, while iterations like loop statements and conditional statements (e.g., If-Else) aren\u2019t supported.\u00a0<\/p>\r\n\r\n\r\n\r\n

FP evolved from the lambda calculus (\u03bb<\/em>-calculus)<\/a>, a simple notation for functions and applications that mathematician Alonzo Church developed in the 1930s. Many programming languages and dialects use the functional paradigm, including Scheme, Common Lisp (CL), and Elixir.\u00a0<\/p>\r\n\r\n\r\n\r\n

Many of today\u2019s top programming languages<\/a>\u2014including C#, Java, JavaScript, PHP, and Python\u2014support programming in a functional style or use features found in FP.\u00a0<\/p>\r\n\r\n\r\n\r\n

The following section will discuss the difference between pure and impure functions in functional programming.<\/p>\r\n\r\n\r\n\r\n

Pure Functional Programming<\/h3>\r\n\r\n\r\n\r\n

Purely functional programming is a subset of FP that treats all functions as deterministic mathematical or pure functions.\u00a0<\/p>\r\n\r\n\r\n\r\n

In deterministic mathematical functions, the development of future states of the system does not allow any randomness. Pure functions, meanwhile, have function return values that are identical for identical arguments. The function application also has no side effects (i.e., it does not modify state variable values outside its local environment).\u00a0<\/p>\r\n\r\n\r\n\r\n

A side effect occurs in a program when you insert external code into your function. This prevents the function from properly performing its task. Impure functions, in contrast, contain one or more side effects.\u00a0<\/p>\r\n\r\n\r\n\r\n

To see pure functions in action, refer to the following JavaScript code:<\/p>\r\n\r\n\r\n\r\n

function updateMyAddress(newAddress) {<\/p>\r\n\r\n\r\n\r\n

\u00a0\u00a0\u00a0const myAddress = [“ChurchSt”, “CovingtonCross”];<\/p>\r\n\r\n\r\n\r\n

\u00a0\u00a0\u00a0myAddresses[myAddresses.length] = newAddress;<\/p>\r\n\r\n\r\n\r\n

\u00a0\u00a0\u00a0return myAddresses;<\/p>\r\n\r\n\r\n\r\n

}<\/p>\r\n\r\n\r\n\r\n

updateMyAddress() doesn\u2019t need any external code to accomplish its tasks. This means it\u2019s a pure function.<\/p>\r\n\r\n\r\n\r\n

Impure Functional Programming<\/h3>\r\n\r\n\r\n\r\n

To see impure functions in action, check out this JavaScript code:<\/p>\r\n\r\n\r\n\r\n

\u200b\u200bconst myAddresses = [“ChurchSt.”, “CovingtonCross”];<\/p>\r\n\r\n\r\n\r\n

function updateMyAddress(newAddress) {<\/p>\r\n\r\n\r\n\r\n

\u00a0\u00a0myAddresses.push(newAddress);<\/p>\r\n\r\n\r\n\r\n

\u00a0\u00a0return myAddresses;<\/p>\r\n\r\n\r\n\r\n

}<\/p>\r\n\r\n\r\n\r\n

updateMyAddess() is an impure function since it contains code (myAddress). This code mutates an external state, which gives updateMyAddress() some side effects.<\/p>\r\n\r\n\r\n\r\n

Why Functional Programming Matters<\/h2>\r\n\r\n\r\n\r\n

While FP has generally been less popular than object-oriented programming, it has grown in popularity in recent years due to the rise of machine learning and big data. Functional programming is notable for its ability to efficiently parallelize pure functions. Code for data analysis workflows and tasks is easier to analyze, test, and maintain using the functional programming paradigm.<\/p>\r\n\r\n\r\n\r\n

Due to its pure nature, FP is ideally suited for analyzing extensive data sets and machine learning. Pure functions will always generate the same results, with no outside values to influence the final results.\u00a0<\/p>\r\n\r\n\r\n\r\n

Algorithms created using FP can also quickly identify and correct errors. Many programmers and software developers would rather work with a programming paradigm that is easy to debug because of its pure functions.\u00a0<\/p>\r\n\r\n\r\n\r\n

As highlighted in a paper published by John Hughes of the University of Glasgow, functional programming plays a crucial role in future tech development because of its modularity. Modularity breaks down large and complex projects into simpler modules. You can test the modules separately, which lessens the amount of time spent on unit testing and debugging.<\/p>\r\n\r\n\r\n\r\n

\u201cFunctional programming languages provide two new kinds of glue \u2014 higher-order functions and lazy evaluation. Using these glues, one can modularize programs in new and useful ways,\u201d Hughes notes in his paper.\u00a0<\/p>\r\n\r\n\r\n\r\n

Advantages of Functional Programming<\/h2>\r\n\r\n\r\n\r\n