Free Recall

• Get out a sheet of paper or open a text editor
• For 2 minutes write down whatever comes to mind about the last class
  • This could be topics you learned
  • Questions you had
  • Connections you made

Setting Up CS Circles

• Sign up for a free account on CS Circles
• This is mandatory
• Next set jhaugh as your “guru”
  • Click “Edit my profile” in the top right menu
  • Set the guru field to jhaugh
• I will now be able to see your progress and give you credit in Canvas

Setting Up OnlineGDB

• In addition to CS Circles we will also be using a platform called OnlineGDB
• This platform will facilitate in class exercises
• Sign up here
• Then join the course here

Exercise: Baker’s Math

• Now you should be able to see an exercise called “Baker’s Math”
• Complete this exercise now
• You are welcome to discuss code with those at your table

Functions

• For now think of functions as code someone else wrote that you can use
• For example, the print() function or the input() function
• There are many more that Python provides you

Function Arguments

• Most functions take arguments
• These arguments allow you to change the behavior of the function
• For example,
  • When you give print a string argument it simply prints that string
  • When you give print a variable argument it looks at the value inside and prints that

Multiple Function Arguments

• Many functions take more than 1 argument
• For example, print may be called with more than 1 argument
• Each argument is separated by a comma
• print with multiple arguments prints each argument and separates each with a space in the output

x = 5
y = 6
print(x, y, "!")

5 6 !

More Useful Functions: Min and Max

• The min function takes in any amount of numbers as arguments and returns the minimum
• The max function takes in any amount of numbers as arguments and returns the maximum

x = 5
y = 50
z = 500
print(min(x, y, z))
print(max(x, y, z))
print(min(x, y, z, 1))
print(max(x, y, z, 1000))

5
500
1
1000

Common Errors

• There a number of common errors that new programmers make when calling functions:

max()

max(3, 5

max(3, x)

Comments

• Comments are invaluable tool for help other programmers understand your code
• They are ignored by Python when running your code
• You can start a comment with a hashtag/pound sign (#)
• For example:

# This is a comment
# It is not read by the program
# It is only for humans to read
print("Hello") # A comment can be here too
# The next line of code will not run
# print("world")

Visualize

Escape Sequences

• Sometimes you need to insert a special character into a string
• This could be a newline, a tab, or even just a quote
• To do this you need to use the backslash (\)
• For example:

print("Hello\nWorld") # Prints Hello World on two separate lines
print("Hello\tWorld") # Prints Hello World with a tab between
print("\"Hello World\"") # Prints "Hello World"

Visualize

Chapter 2 & 3

Take the remaining time to complete all of the exercises in chapters 2 & 3