Reusable named blocks that take parameters and return values.
Functions package reusable logic with parameters and return values. Benefits: abstraction, testing and avoiding repetition. Ideas: pure functions, default and keyword arguments, scope, recursion, higher-order functions and lambdas. Keep functions small and well named.
def area(r): return 3.14159*r*r.
Functions break a program into reusable parts, which makes code easier to test, change and understand.
Reusable named blocks that take parameters and return values.
Functions break a program into reusable parts, which makes code easier to test, change and understand.
It does one clear job, has well-named parameters, returns a predictable result and avoids hidden changes to shared state.
A change outside the function, such as writing to a file or changing a global variable, which makes behaviour harder to predict.
Typical applications include writing a unit conversion function used in many places, separating the logic that reads a sensor from the logic that displays it and creating a function that validates an email address.
Study "Loops" first (topic 6 of 104 in Software & Computing). It covers the groundwork this topic builds on.
Call stack. Pass by value vs reference. Docstrings.
def area(r): return 3.14159*r*r.
The next topic is "Arrays and lists", which builds directly on this one.
It is classed as Beginner in Software & Computing (topic 7 of 104). It is an entry-level topic. It relies only on basic school mathematics and the ideas introduced earlier in this discipline.
Want to practise? Open the interactive course for quick checks, quizzes, simulations and progress tracking.