Our First Summer Meeting!
Updated: Oct 19, 2020
On July 1, 2020, Phillips Exeter Academy Girls who Code had our first meeting of our summer program with five of our wonderful students!
We started off by introducing ourselves to each other. Then we went over the brief history of Python and its increasing usage in the industry and among the programmers. The materials we went over can be viewed in the powerpoint attached below:
Recap of our first class:
1. Installing Python IDLE
Go to this link, and download Python that matches your OS (Operating System - Mac, Windows, Linux, etc.)
After you finish the download, open the file and start installing Python on to your computer.
2. Open IDLE
If you are a Mac user, you will see this icon appearing in your Applications. Click on this.
If you are a Windows user, do a search and look for 'Python IDLE.'
If you have opened correctly, you should see 'Python Shell' as the name of the new window.
3. Python Syntax 1 - Print statement
Python is a high-level language, which means that its commands are similar to human language - in this case, English! So, you can probably understand what each python command does just by looking at it.
A print statement in Python literally prints the statement you specify on to your screen.
To write a print statement, you do:
This is a classic example:
>>> print ("Hello, world!") Hello, world!
Notice that the statement is in quotation marks. This is because Python needs a way to tell the difference between a normal text and Python commands. By using quotation marks around the text, we tell Python that it is a text input, not a Python command.
Try with your own statement
4. Python Syntax 2 - Math Operators
Just like how we do math in our classes, we can use Python to do some math - and use it like a calculator!
These are the math operators we use in Python:
Addition: + >>> 3 + 2 5 Subtraction: - >>> 3 - 2 1 Multiplication: * >>> 3 * 2 6 Division: / >>> 4 / 2 2 Exponent: ** >>> 2**2 4
5. Basic data types in Python
There are different types in Python - just like how we have number, text, etc.
Integer (Whole number): int String (Text): str Float (numbers like 2.5, 5.49, etc.): float Boolean (True/False): bool
You do not have to know the abbreviations (like int, str) for now.
Doing the following tells you the type of your input:
type(something) >>> type(3) <class 'int'> >>> type("hello") <class 'str'>
6. Comparison Operators
Comparison operators let you compare different things of the same type.
If you compare two things of different type (for example, 3 and "hello"), you will get an error.
Operators will return results in boolean - either True or False.
Equal: == Not equal: != Greater than/Smaller than: > or < Greater than or equal to/Smaller than or equal to: >= or <= >>> "hello" == "hello" True >>> 3 == 1 False
Note that unlike in math, you use == to check if two objects are equal, not =.
Generally in programming, = is used for setting values for variables.
pig = 3
This line of code sets the value of variable pig to 3.
7. Conditional statements
Conditional statements evaluate the statement you have input and runs the commands within it ONLY IF the statement is TRUE.
In English, you often say sentences with if, just like this example:
If you play the piano for me, I will get you a cookie.
You can do a similar thing in programming languages. You specify a certain condition after 'If,' and the statements you write within the curly brackets that follow if will only be executed if the condition is met.
General If statement structure in Python:
If (condition): do something elif (condition): do something else: do something
elif in Python means 'else if' in English.
Elif statement will only be evaluated if If statement is false. Similarly, else will only be evaluated if both if and elif statements are false.
if (3 < 2): print ("2 is bigger than 3") elif (3 > 2): print ("3 is bigger than 2") else: print("3 is equal to 2") 3 is bigger than 2
Quick Note: Make sure you run this in a Python file not a shell. (If you are a Mac user, do File > New File) Then you save the file and do Run > Run Module.
For those who weren't able to come to our first meeting:
You can still sign up for our summer program!
Sign up, and let me (Rachael Kim, firstname.lastname@example.org) or Mana Vale (email@example.com) know if you need to schedule a make-up session for classes you missed. If you already know these basic syntax, that's also cool! We will be learning graphic libraries of Python such as tkinter, turtle, etc. in the upcoming weeks, so you should join us in the journey!