What is Functional Programming?

Functional programming is a programming paradigm that emphasizes evaluating functions and avoiding changes in state and mutable data. In functional code, the output value of a function depends only on the arguments to the function, so calling a function f twice with the same value for argument x will produce the same result f(x) each time, regardless of when or where the function is called. This is in contrast to imperative programming, which relies on changes in state to perform computations. Functional programming is commonly used in areas such as data analysis, scientific computing, and concurrent programming.