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Understanding the Fold Function

Prakhar takes us through the fold function in functional programming, using Scala as the language of choice:

“fold” is a common operation in programming languages including Scala where we essentially use it to “reduce” (note that “reduce” is also an operation in programming languages and has a special meaning in Scala as well). In this blog, we will learn how to use the fold function, understand different types of fold operations (including foldLeft and foldRight), and try to understand how it all works. Although fold operation can be applied on Option, Future, Try, etc.. but here we will understand it through List

Fold is extremely useful for things like “I want to calculate a sum but it’s got to be a conditional sum” or when you have more complex mathematical operations to combine elements together. It can take a while to get comfortable with the syntax, but once you do, it opens mental doors.