How MapReduce works

MapReduce is a programming methodology used for writing programs on Apache Hadoop. It allows the programs to run on a large scalable cluster of servers. MapReduce was inspired by functional programming (https://en.wikipedia.org/wiki/Functional_programming). Functional Programming (FP) offers amazing unique features when compared to today's popular programming paradigms such as object-oriented (Java and JavaScript), declarative (SQL and CSS), or procedural (C, PHP, and Python). You can look at a comparison between multiple programming paradigms here. While we see a lot of interest in functional programming in academics, we rarely see equivalent enthusiasm from the developer community. Many developers and mentors claim that MapReduce is not actually a functional programming paradigm. Higher order functions in FP are functions that can take a function as...