Shubham Shrivastava explains how lambda expressions work in Scala:
Lambda expressions in Scala the syntax for these uses a symbol it’s an equals and a greater than and we refer to this as rocket ( => ). When we’re reading the code the idea of a lambda expression is a short literal expression that defines a function and typically these should not be overly long. so for example I could define a function for squaring values that looks something like this.
Lambda expressions are great in cases where you need to perform an operation exactly one time. If you create a separate function with its own name, there’s always a wonder in the back of a developer’s mind if this thing will get used again, and so it takes up a little bit of cognitive load. A lambda expression answers that conclusively: no, we won’t use this code again.