OpenBrackets

Beginning Programming

Week 2 Day 1

Welcome!

Welcome to class!

This is the Starting Programming class

• 5 - 6:30pm : 5 min break towards the middle�
• Teachers and TAs are:
• Aidan, Kevin, Rohan, and Sean

​

• No grades - but the more we can help each other learn as a group, the better

Have a question?

Ask a teacher or TA

Type in chat

Or

1. Click Reactions
2. Click Raise Hand

​

Or un-mute and speak up

Previously on OB...

• Setup repls
• Printed out a joke
• Got user input
• Saved values in variables
• Made some calculators with those values

Remember you can store values in variables

Variables have a name

Like labelling a new place on a bookshelf

Don't put the name in quotes, just put something in that place

Operators are for doing math (and more) with values

A small portion of code is called an "expression"

​

Here's some more expressions to try --->

1 + 1

55 / 11

3*2

10 - 611

1000000 * 1000000

Symbols like + / - * are called "operators"

More ways to share - you can do "multiplayer" on repls

1. click here

2) Then share the link

Group exercise - write MadLib code

• Let's write a program that asks the user for some values, like:� a_mood # like thrilled� an_animal # like a wombat� a_place # like a hair salon� an_activity # like skiing� a_number # like four
• After taking inputs, print() out the story,� for example:�"I was thrilled to see a wombat in my local hair salon, because I normally only see four of them when they are skiing."

Values and operators can be grouped with ()

2 + 2 * 3

( 2 + 2 ) * 3

4 * 3

​

​

( 2 + 2 ) * ( int(input()) + 1 )

Some more types

Can you make one of each of these, and test with type()?

Some operators work with int and str values

You can combine strings using the + operator

How can you combine a str and an int?

You can convert any int into a str using str() function

type(12)

type(str(12))

"there are " + 12

"there are " + str(12)

You can convert any str into a int using int() function

"there are " + str( 12 + int("12") )

Group exercise - write a Time Factorializer

Ask the user to enter their age in years.�Print out:

• The number of months that is
• The number of weeks that is
• The number of days that is
• The number of hours that is
• The number of minutes that is
• The number of seconds that is

Make sure to print out text labelling which is which. Work together!

The Error-o-dex

• print 5 → SyntaxError: Missing parentheses in call to 'print'. � Did you mean print(5)?
• print (1+*2) → SyntaxError: invalid syntax
• Print (1+2) → NameError: name 'Print' is not defined
• a/2 → NameError: name 'a' is not defined
• "2"/2 → TypeError: unsupported operand type(s) � for /: 'str' and 'int'
• print(5 + 'a') → TypeError: unsupported operand type(s) � for +: 'int' and 'str'
• sentence = "hi → SyntaxError: EOL while scanning � string literal

5 minute break!

• Turn your camera off
• Get a drink of water
• Stand up and stretch

​

Let's actually make a game!

Carl the Goblin is trying to "liberate" an book of spells from a private library guarded by trolls

...however...

Carl is not a warrior

Carl does know some illusion spells though!

​

Can Carl make the right choices to sneak in and get the book?

Logical operators can check if values are equal or not

• = assigns the value on the right to the variable on the left�BUT
• == is used to check whether the left and the right side have the same value
• != is used to check if the left and the right side have a different value

Operators like == and != return values like True and False

These are called "boolean" or "logical" values

== and != are operators

You can test if values are equal - or not !

choice = "A"

print( choice )

print( choice == "A" )

print( "choice is equal to A: " + (choice == "A") )

print( "choice is equal to A: " + str(choice == "A") )

print("choice is not equal to A: "+str(choice != "A"))

print(type(choice != "A"))

​

bool aka boolean aka logical

type(True)

type(False)

True == True

True == False

False == False

Reminder:

​

You can test things out in the console

Click in Console, type, and press enter

​

Difference: everything is "print"-ed out to you�'Run' code is not automatically "print"-ed

Conditionals are how your program "thinks"

• Conditionals allow the code to make decisions based on bool values like True and False
• The most basic is an if statement

For examples, try these blocks, and change them to change the behavior:

if True:

print("true is true")

if False:

print("false is true")

Indentation is important!!

What is wrong with the code below?�

if True:

print("huh?")

IndentationError: expected an indented block

How to fix it? Add tab/spaces before print to indent it

if True:

print("huh yeah")

Exercise

What should this code produce?

if 2 + 2 == 3:� print("2 + 2 is 3")�

condition = 2 + 2 == 3�if condition:� print("2 + 2 is 3")

​

How do we ask if the user likes apples, and print "you like apples" if they respond yes?�Remember the input() function?

if true - or else !

else: is something you can put under an if condition:

if the if condition: is not true, the else: will run

What should this code produce?

if 2 + 2 == 3:� print("2 + 2 is 3")�else:� print("2 + 2 is not 3")

Write a choice-adventure game

• Print out the scenario (Carl the Goblin is trying to get the book o' spells)
• Print out a choice � ex: "Trolls! sneak or fight or illusion?"
• Then print if they picked an option, like "fight"
• Test it out!

Group exercise

_nnnn_

dGGGGMMb

@p~qp~~qMb

M|@||@) M|

@,----.JM|

JS^\__/ qKL

dZP qKRb

dZP qKKb

fZP SMMb

HZM MMMM

FqM MMMM

__| ". |\dS"qML

| `. | `' \Zq

_) \.___.,| .'

\____ )MMMMMP| .'

`-' `--'

​

Can you draw something by printing strings? ----->

​

Work together to draw a picture of an animal (or animals)

Copy and paste! Share!

What letters / symbols work best?

How do you do lots of lines?

​

Starfish? Fish? Bat? Snail? Crab? Worm? Cat? Dog?

When you need help outside class

Email openbracketscoding@gmail.com and say what class and teacher you have

• Don't email teacher directly.

If you are age 13 or older, you can try Discord

• https://discord.gg/ZRtk534

The age restriction is because of Discord’s Terms of Service

Thanks for coming to class!

Please let us know if you have any questions!