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Resources from lecture

• Link to all code written in lecture

Today’s lecture:

• Working with strings and lists
• Functions: Using existing ones, defining new functions

Concept Questions

• Check your understanding: Lect 03 Concept Questions
• You’ll need your iclickers to participate in class

Function definition

def double(n): ‘’’ Returns 2 times the parameter ‘’’ return 2 * n

’’’

• The “def” indicates a function definition
• “double” is the name of the function
• (n) denotes the parameter(s) of a function
• name + parameters is known as a function SIGNATURE
• The actual code (instructions) (ex: return 2 * n) is known as the function BODY
• Note: The function body needs to be indented so python can associate the body’s instructions as part of the function’s definition
• If the function returns a value, then a RETURN statement is needed ‘’’

  Examples calling double()

  print(double(10)) # –> print(20) print(double(double(2))) # –> print(double(4)) –> print(8) value = double(5) + double(6) print(value)

print(double(“2”)) print(type(double(“2”))) print(double(2.5)) print(type(double(2.5))) print(double([2,4,6]))

pytest

Good defensive coding style means that you think about how you would test your code.

• Overview of lab01 and how to use the pytest framework

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