Python

Learn Python programming with simple, clear examples

CONTENTS

1. Introduction
2. Variables
3. Numbers
4. Strings
5. Lists
6. Functions
7. Loops
8. Conditions
9. Dictionaries
10. Classes
11. Error Handling
12. Project

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Introduction

In this course, you’ll learn about the basics of python programming.

Let’s print “Hello World”.

print("Hello World")

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print("Hello World")

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Variables

Variables store values. Python figures out the type automatically.

name = "Alice"
age = 25

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# Try creating your own variables name = "Alice" age = 25 print(name) print(age)

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Numbers

Python handles integers and floats. Math works as expected.

x = 10
y = 3
sum = x + y

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# Try some math x = 10 y = 3 print(x + y) print(x * y) print(x / y)

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Strings

Strings are text wrapped in quotes. Use + to combine them.

greeting = "Hello"
name = "World"
message = greeting + " " + name

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# String operations greeting = "Hello" name = "World" print(greeting + " " + name) print(f"{greeting} {name}") # f-strings

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# Create your sentence here

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Lists

Lists hold multiple items in a specific order. Each item has a position number called an index, starting from 0.

fruits = ["apple", "banana", "orange"]
first_fruit = fruits[0]

Lists are created with square brackets and items separated by commas. You can access any item by using its index number in square brackets.

Exercise

Create a list called colors with “red”, “green”, and “blue”. Remember to use quotes around each color name.

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# Create your list here

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Functions

Functions are reusable blocks of code that perform specific tasks. They can take input (parameters) and return output (results).

def greet(name):
    return "Hello, " + name

message = greet("Alice")

Functions are defined with the def keyword, followed by the function name and parameters in parentheses. The return statement sends a value back to whoever called the function.

Exercise

Create a function called add that takes two numbers as parameters and returns their sum. Use the def keyword and return statement.

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# Create your function here

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Loops

Loops repeat. For each item. Do something.

numbers = [1, 2, 3, 4, 5]
for num in numbers:
    print(num * 2)

Exercise

Print each number from 1 to 5.

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# Create your loop here

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Conditions

Conditions check. If true, do this. If false, do that.

age = 18
if age >= 18:
    print("Adult")
else:
    print("Minor")

Exercise

Check if a number is positive. Print “Positive” or “Negative”.

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number = 10 # Add your condition here

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Dictionaries

Dictionaries map keys to values. Look up. Find.

person = {
    "name": "Alice",
    "age": 25,
    "city": "New York"
}
print(person["name"])

Exercise

Create a dictionary called book with “title” and “author” keys.

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# Create your dictionary here

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Classes

Classes create objects. Blueprint. Template.

class Person:
    def __init__(self, name):
        self.name = name
    
    def greet(self):
        return "Hello, I'm " + self.name

alice = Person("Alice")
print(alice.greet())

Exercise

Create a class called Car with a brand attribute and a start method.

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# Create your class here

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Error Handling

Errors happen. Catch them. Handle them.

try:
    result = 10 / 0
except ZeroDivisionError:
    print("Cannot divide by zero")

Exercise

Try to access an index that doesn’t exist in a list. Catch the error.

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numbers = [1, 2, 3] # Add your try-except here

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Project

Create a simple program. Use everything you learned.

class Calculator:
    def __init__(self):
        self.history = []
    
    def add(self, a, b):
        result = a + b
        self.history.append(f"{a} + {b} = {result}")
        return result
    
    def show_history(self):
        for entry in self.history:
            print(entry)

calc = Calculator()
calc.add(5, 3)
calc.add(10, 20)
calc.show_history()

Exercise

Create your own calculator with multiply and divide methods.

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# Create your calculator here

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Conclusion

You learned Python. Variables. Functions. Classes. Loops. Conditions.

Simple. Clear. Direct.

Python is powerful. You are ready.