Functions in Python are defined using the 'def' keyword followed by the function name and arguments. Functions return values using the 'return' statement and do not declare argument or return types. Python allows functions to be passed as arguments to other functions or used anonymously without naming. Python is popular for scientific programming due to its easy syntax, built-in data types, ability to run on many systems, large library of scientific packages, large user community, and use in universities.

1. Functions

4. colon
start with ‘def’
function name
arguments
deftwotimes(n):
return2*n
‘return’ precedes
the value to be sent back
No declaration of types
of function or arguments

5. New definition?

6. New definition?

7. New definition?

8. Popquiz!
What happens now?

9. Popquiz!
What happens now?

10. No ‘overloading’

11. More functions

12. What does this mean?

13. Functions can be arguments

14. Functions can be arguments

15. We can also use an “anonymous function”

16. Using parameters

27. Why Python?
•Easy to learn syntax
•Built-in datatypes for lists, strings etc.
•Runs on many types of machines
•Many scientific librartes (SciPy, NumPy)
•Large community of scientists using it
•#1 programming language in universities
•Shell mode for experimentation

28. Why Python?
•Easy to learn syntax
•Built-in datatypes for lists, strings etc.
•Runs on many types of machines
•Many scientific librartes (SciPy, NumPy)
•Large community of scientists using it
•#1 programming language in universities
•Shell mode for experimentation
•Awesome Excel integration