Unit 9 - Functional Approaches - Comprehensions, Lambda, Closures And Higher-Order Functions

What Is A Pure Function?

• A function whose return value depends only on its arguments, with no side effects

• Actions that affect the external state of a program, such as modifying a global variable or performing I/O

What Is The Primary Advantage Of Immutable Data Structures?

They prevent unexpected changes to values, eliminating aliasing issues and making code easier to reason about

What is a list comprehension?

A concise way to create lists by applying an expression to each element of a sequence, optionally filtering elements

What is the difference between using if at the end of a comprehension versus within the expression part?

At the end, if acts as a filter, removing elements - within the expression, it conditionally evaluates to one of two values for each element, without changing the number of elements

What is a closure?

A function that “closes over” variables from its enclosing scope, remembering them even after the outer function has finished executing

What is reduce used for?

To apply a two-argument function cumulatively to the items of a sequence, reducing it to a single value

What does zip do?

It takes multiple sequences and returns an iterator of tuples, where the i-th tuple contains the i-th element from each of the input sequences

What is a lambda expression?

An anonymous function defined using the lambda keyword, typically used for short, one-off functions within an expression

What is recursion essential in pure functional programming?

Because pure functional programming avoids mutable variables and loops, recursion is the primary mechanism for repeating operations

Data Flow Model

Functions are nodes, data as edges - powers parallel systems

nonlocal Purpose

Modify a variable in an outer (non-global) scope from within a nested function

Recursive Function Structure

• Base Case: Trivial solution, stops recursion

• Recursive Step: Call itself with modified args, moving towards base case