Python Basics

# Hello world
print("Hello world!")

# Hello world with a variable
msg = "Hello world!"
print(msg)

# f-strings (using variables in strings)
first = 'albert'
last = 'einstein'
full = f"{first} {last}"
print(full)  # albert einstein

# Making a list
bikes = ['trek', 'redline', 'giant']

# Get first and last item
first = bikes[0]  # trek
last = bikes[-1]  # giant

# Looping through a list
for bike in bikes:
    print(bike)

# Adding items to a list
bikes = []
bikes.append('trek')  # add to end
bikes.insert(0, 'giant')  # insert at position

# Simple dictionary
alien = {'color': 'green', 'points': 5}

# Accessing a value
print(alien['color'])  # green
alien.get('points', 0)  # safe access with default

# Adding new key-value pair
alien['x_position'] = 0

# Conditional tests
x == 42  # equal
x != 42  # not equal
x > 42  # greater than
x >= 42  # greater or equal

# Simple if statement
if age >= 18:
    print("You can vote!")

# If-elif-else chain
if age < 4:
    price = 0
elif age < 18:
    price = 10
else:
    price = 40

# Simple function
def greet():
    print("Hello!")

greet()

# Passing an argument
def greet(username):
    print(f"Hello, {username}!")

greet('jesse')

# Returning a value
def add(x, y):
    return x + y

sum = add(3, 5)  # 8