Python Basics Tutorial

1. Variables

Variables are containers for storing data. In Python, you can assign values directly without declaring types.

# Variable assignment examples
name = "John"
age = 25
height = 1.75

Python automatically identifies data types: string, integer, float, etc.

2. Data Types

Python has the following basic data types:

# Data type examples
text = "Hello World"      # String
number = 42               # Integer
decimal = 3.14            # Float
is_true = True            # Boolean
items = [1, 2, 3]         # List

3. Basic Operations

Python supports various mathematical and logical operations:

# Arithmetic operations
a = 10 + 5    # Addition
b = 10 - 3    # Subtraction
c = 10 * 2    # Multiplication
d = 10 / 3    # Division

# Comparison operations
x = 5 > 3     # True
y = 5 < 3     # False
z = 5 == 5    # True

4. Conditional Statements

Use if, elif, else to execute different code blocks based on conditions:

age = 18

if age < 18:
    print("Underage")
elif age == 18:
    print("Just turned adult")
else:
    print("Adult")

5. Lists

Lists are ordered collections that store multiple items:

# Create a list
fruits = ["Apple", "Banana", "Orange"]

# Access element
first_fruit = fruits[0]    # "Apple"

# Add element
fruits.append("Grape")

# Iterate over list
for fruit in fruits:
    print(fruit)

6. For Loops

For loops are used to iterate over each element in a sequence:

# Iterate over list
animals = ["Dog", "Cat", "Bird"]
for animal in animals:
    print("I like", animal)

# Numeric loop
for i in range(5):
    print("Number:", i)

7. While Loops

While loops repeat code blocks while the condition is true. This is the most important loop structure in The Farmer Was Replaced:

# Basic while loop
count = 0
while count < 5:
    print("Count:", count)
    count = count + 1

# Infinite loop (common in games)
while True:
    # Get the next action
    action = get_next_action()
    if action == "Stop":
        break
    execute_action(action)

8. Functions

Functions are reusable code blocks that perform specific tasks:

# Define function
def greet(name):
    return "Hello, " + name + "!"

# Call function
message = greet("Xiao Ming")
print(message)

# Function with multiple parameters
def calculate_area(length, width):
    return length * width

area = calculate_area(5, 3)
print("Area:", area)