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1. What is This Course?

This is a beginner course for middle school students who want to gain basic CS Skills
Computer Science (CS) is the study of different problems and the ways we can code to solve them. Although there are countless different languages, each with their own unique features and drawbacks, these basic concepts can be applied to almost all of them
CS allows us to approach complex problems and break it down into smaller pieces that we can manage, this is an important skill you'll need to use in many parts of your day-to-day

2. What Resources Do I Need?

Follow along and learn while typing! We will be using a free online compiler called Programiz for all of our programs. Link: https://www.programiz.com/python-programming/online-compiler/

Handy Dandy Programiz Guide:

Programiz Notes:

Make sure Python is selected (top left).
We write our code in the left box. This is our miniature program file. When you click the "Run" button, the program outputs in the right box. Use the clear button to clear output.
If your program outputs an error, your code needs a fix. Common errors include: missing marks ( , : () # ), misspelled functions, and improper formatting

Patience and time

You will need to read and understand the modules and code that we have provided
There will be a `Do It Yourself` challenge at the end of each module that we encourage students to complete on their own, without any notes

3. How Can I Make the Most of It?

Move in small chunks

Instead of running through this course in a single day, go by each module day by day or week by week
Make sure you're understanding the concepts and know how to apply them, rather than just copy and paste code

Do the practice assignments

Practicing is the only way to really perfect these concepts
If you run into errors, try to debug the code and understand what each line does

Follow the resources

We've linked many different resources within each module to help you understand each piece correctly, use them whenever you need

Break it down

Nothing we present will be impossible since this course is carefully crafted for most beginner audiences with no prior experience
Break down complex concepts/ homework assignments into pieces that you understand and can attack individually

4. Closing Notes

We're glad you chose this course to guide you through the basics of CS
We hope that you're able to learn and apply these new concepts in all aspects of your educational and professional career
Good luck!

Variables and Printing

Choosing a Variable Name

Only use alpha-numeric characters and underscores (A-z, 0-9, and _ )
The name needs to start with a letter or underscore character
Cannot start with a number
Are case-sensitive (var, Var and VAR are three different variables)

Legal Variable Name Examples:

myvar = “Sam”
my_var = “Sam”
my_var = “Sam”

Illegal Variable Name Examples:

7myvar = “Sam”
my-var = “Sam”
my var = “Sam”

Variable Declaration

Python has no command for declaring a variable so datatype are automatically assigned

x = 3 -> automatically assumed to be an int
y = “Tom” -> automatically assumed to be a string

type() function

To check the data type assigned to your variable, use the type() function

Casting

To specify the data type of a variable, use casting

x = str(3) -> the integer is now turned into a string -> ‘3’
y = int(‘3’) -> the string is now turned into a integer -> 3

Printing

print() function allows you to output variables
Components: print(object(s), sep=separator, end=end, file=file, flush=flush)

x = "Python"
y = "is"
z = "awesome"

Utilizing print systems:
Automatically assumed to use “ “ as separator

Use a different separator(“—“)

Can separate variables using “+” as well

Carefully add separators when using “+”

Arrays

An array is a special variable that can hold more than one value at a time.

Using an Array

When you have a list of items instead of making multiple variables like this:

name1 = “Fred”

name2 = “George”

name3 = “Sally”

Solution is to use an array

names = [“Fred”, “George”, “Sally”]

Accessing Array Elements

To access element in array:

names[0] -> this accesses element “Fred”

To change element in array:

names[0] = “Bob” -> this allows the first element to now be “Bob” instead of “Fred”

Conditions

What are conditions? and why?

Conditions are pieces of code that makes your program does different actions based on each situation
Without conditions, one program can only do a single thing, no matter what the actual situation is
Without conditions, your program will fail and crash if it encounters a situation you hadn't thought of

Let's Check Common Conditional Code in Python!

Types of Conditions

Equals: a == b, this will check if a is equal to b, and return true or false base on each case
Not Equals: a != b , this will check if a is not equal to b, and return true or false base on each case
Less than: a < b , this will check if a is less than b, and return true or false base on each case
Less than or equal to: a <= b, this will check if less than or equal to b, and return true or false base on each case
Greater than: a > b, this will check if a is greater than b, and return true or false base on each case
Greater than or equal to: a >= b, this will check if a is greater than or equal to b, and return true or false base on each case

Check out the following example below:

Those conditions can help you get true or false base on different situation, so that the code can react differently to that true or false and has a different behavior. However, just having these conditions is not enough, let's learn another important python statement in next section if/else statements

If, else and elif?

if statement will check the true of false of its condition and decide which part should be run.
elif will run its part of code when its condition statement turn to be true.
else statement will run its code only when if statement and all the elif turn to false.

Check out this example!

Loops

What Are Loops?

Loops are a sequence of instructions that are continually repeated until a certain condition is reached. We can use loops to repeat an instruction multiple times!

Types of Loops

For Loop

While Loop

Let's Make a For Loop!

Let's Make a While Loop!

Useful feature of a for loop in Python!

A useful feature of for loops in python is that you are able to iterate through a list/array without having to index the list.

Instead of doing this:

we can do this:

A for loop allows you to be able to access every item in a list/array even if you dont know how many items are in the list/array. This is very useful for things such as reading from files.

Loop Dangers!

Infinite Loop

An Infinite Loop is a continuous repetitive conditional loop that gets executed forever. Now an infinite loop will not necessarily run forever, it will eventually end when the computer runs out of memory. However, this is something you should avoid becuase your program will hang.

You can end up in an infinite loop if you don't have a condition that is met in your loop.

For Example:

In the above image you can see the loop will never exit because x will never be less than -2

Functions

What Are Functions?

Functions are structures that allow us to complete a series of actions in our program. We use them to perform tasks!

Example (read the comments!):

Types of Functions

Built-in functions: functions that Python provides for us like print() and input()!

Take a look at Python Docs to see all of Python's built-in functions. Scroll down to see what they do!

User defined functions: functions that programmers create to accomplish specific tasks in their program.

Function Structure:

Let's analyze our "do_something()" function from before:

Every function in Python starts with def, followed by the function name, and ():

"Parameters" are optional inputs that the function uses and changes. Parameters go inside the parentheses. (more on that later)

def makeTable():, def greet(name):, and def add(num1, num2): are all valid first lines of a user-defined function.

Every function also contains a body.

This is where we add statements to complete our tasks
In the do_something() function, our body completes 3 tasks:

prints "Look I'm doing something"
prints 5 *s
prints "Look I'm doing more!!!"

Calling a function causes the function body to execute. To call a function, simply write the function name followed by parentheses. If the function takes parameters, put them inside the parentheses.

makeTable(), greet("John"), and add(x, y) are all valid function calls.

Let's take a look at another example (with parameters!):

This add function takes in two parameters (num1, and num2).

num1 and num2 reserve spots for numbers or variables that contain numbers!

This function returns the sum of num1 and num2.

Notice that unlike do_something(), add(num1, num2) prints nothing to the console!

This is because the do_something() function prints within the function.

In order to see if our add function is working properly, we can call the function within a print statement!

User Input!:

When programs need the user to provide information, it takes in user input. Here, we will learn how to use the built-in Python function input() to store what the user provides for us.

Below is the definition of a "greet" function that asks the user for their name and says "Hello user name , how are you?":

Inside of input(), we pass a prompt. This prompt shown to the user before they provide their input. We typically choose prompts that tell the user what they are supposed to do. This is what you should see when your program runs:

The computer is asking for your name! Do you see the cursor on the console? Write your name and hit enter!

What really happens here when you hit enter is whatever you typed to the console is then stored in variable, name. Then, our function prints the greeting statement with whatever you entered to the console (see image below). Pretty cool right?

Challenge Problem: Cats or Dogs

Define a function named cats_or_dogs that takes no parameters. Ask the user "Which is better? cats or dogs: ". If the user inputs "cats", the console should respond with "Meow!". If the user responds with "dogs", the console should respond with "Bark!" If the user inputs something other that "cats" or "dogs", the console should tell them "You can only answer cats or dogs. Try again!", then the prompt appears again.

Hints:

Use conditionals since we are checking for different inputs. If this happens -> then do this

We use == to determine if two values are the same. Strings are values!

Solution

Don't be intimidated by the code. Read it line by line and try to understand what it's doing!

Summary:

In this module, we covered:

Functions: built-in & user defined
Function Structure
Parameters
User Input

* Hopefully, completing this module helped you understand the significance of functions. Functions are very common and important structures used in programming. We use functions in our programs to do things! What would programs be if they couldn't do things?

Where Can I Use These Skills?

So you've acquired a slew of new skills after this course, where can you use them? It is important to realize that no matter where you work or what the situation is, having a toolbox of skills will always be helpful, even if you don't directly apply the skills to that specific job.

Analytical Thinking/ Logic

Day-to-day basis where you need to analyze what you need to do for a problem
Classes, college, sports, and more
Hard/Natural sciences like Chemistry and Physics

Breaking the Problem Down

Classes like Science and Math
Where you're dealing with a problem that seems too big to handle on its own

CS-Related Jobs

Game Development

Program in C# to create video games

Software Engineer

Program in a variety of languages in order to make apps, games, websites, and much more

Machine Learning Engineer

Usually in Python, ML engineers create some of the leading technologies we see

Computer/Hardware Engineer

Designing and understanding the hardware of a computer, you'll need a core understanding of CS

Data Scientist

Combining CS (usually Python or R) with statistics

Outside of CS

Mathematician

To help with large math problems, you can programatically solve the problem

Chemist

From 3D models of molecules to reaction simulators, you can create/use many softwares for Chemistry

Researcher

As a researcher with access to huge amounts of data, you'll need to sift through them using Data Science/ CS

Physicist

To simulate/project ideas to see if they're sound, you'll use many softwares

Finance/ Business in General

Algorithm trading or just making a prediction on whether something is a good investment or not

Rock, Paper, Scissors!

Apply the concepts you've learned in modules 1-5 to make a program that plays rock, paper, scissors with the user!

Think about what pieces you'll need from what you've just learned?

Variables to store information like player names?

User Input to take in what your response will be?

Conditional statements to see who wins?

Maybe a loop to play the game over and over?

Step 1

"import random" into your program. This will allow us to genereate random choices from the computer's side. (We'll see how to use it later)

Step 2

We need to know what the user chose, and what the computer chose. Do not fear, we will show you how to know what the computer "chose".

First, store what the user chose. We learned how to do this with user input. We'll accept the inputs: "rock", "paper", or "scissors".

Next, we're going to use our import of "random" to store the computer's choice. Like so:

As you can see, we've made an array of possible actions, and we make the computer randomly choose among those actions.

Step 3

The last thing we need to do is compare the user action and computer action and display a tie, win, or lose message.

Think of all the possible cases. What structures do we use when there are multiple cases?

Cases:

User action is the same as computer action
User chooses rock

Computer chooses scissors
Computer chooses paper

User chooses paper

Computer chooses rock
Computer chooses scissors

User chooses scissors

Computer chooses paper
Computer chooses rock

~ Solution ~

Hover here to see our solution!

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