def buyCoffee(cc: CreditCard): Coffee = val cup = new Coffee() cc.charge(cup.price) // Side effect: hits the bank API immediately cup Use code with caution. Copied to clipboard Learning Functional Programming with Scala | by Ryan Susana
: A function is "pure" if it always returns the same output for the same input and has no side effects (like printing to a console or updating a database). Functional Programming in Scala
To write functional Scala, you need to master three fundamental concepts: def buyCoffee(cc: CreditCard): Coffee = val cup =
Consider a simple task: buying a coffee. In a standard imperative style, you might have a side effect where the credit card is charged immediately. In a functional style, you return the charge as a to be processed later. Impure Code (Side Effect): In a standard imperative style, you might have
: In Scala, functions are first-class citizens. You can pass them as arguments to other functions (like map , filter , or flatmap ) or return them as values.
Scala provides several built-in tools that make functional patterns elegant and concise:
