Basic Python Tutorial

Python is a simple, powerful programming language that is suitable for both beginners and professional developers. This tutorial will introduce the basic concepts of Python.

1. Introduction to Python

Python is a high-level, interpreted, general-purpose programming language, first released by Guido van Rossum in 1991. It has the following features:

Simple and readable syntax

Cross-platform compatibility

Rich standard library

Supports multiple programming paradigms (object-oriented, functional, procedural)

Large community support

2. Installing Python

1. Visit the official Python website

2. Download the version suitable for your operating system

3. Run the installer and check the “Add Python to PATH” option

4. Complete the installation

5. Verify the installation:

python --version# or python3 --version

3. Your First Python Program

Create a file named hello.py with the following content:

print("Hello World!")

Run the program:

python hello.py

4. Basic Syntax

1. Comments

# This is a single-line comment"""This is a multi-line comment"""

2. Indentation

Python uses indentation to indicate code blocks (usually 4 spaces)

if 5 > 2:    print("Five is greater than two!")

3. Variables and Data Types

Variables

x = 5           # Integer
y = "Hello"     # String
z = 3.14        # Float

Basic Data Types

Integer (int): 5, -3, 0

Float (float): 3.14, -0.001

String (str): “hello”, ‘world’

Boolean (bool): True, False

NoneType: None

4. Type Conversion

x = str(3)      # "3"
y = int("5")    # 5
z = float(3)    # 3.0

5. Operators

Arithmetic Operators

+   # Addition
-   # Subtraction
*   # Multiplication
/   # Division
%   # Modulus
**  # Exponentiation
//  # Floor Division

Comparison Operators

==  # Equal
!=  # Not equal
>   # Greater than
<   # Less than
>=  # Greater than or equal to
<=  # Less than or equal to

Logical Operators

and  # And
or   # Or
not  # Not

6. Control Flow

If Statement

x = 10
if x > 0:    print("Positive")
elif x == 0:    print("Zero")
else:    print("Negative")

For Loop

for i in range(5):  # 0 to 4    print(i)
fruits = ["apple", "banana", "cherry"]
for fruit in fruits:    print(fruit)

While Loop

count = 0
while count < 5:    print(count)    count += 1

7. Functions

Defining Functions

def greet(name):    """This is a greeting function"""    return f"Hello, {name}!"
print(greet("Alice"))

Parameters and Return Values

def add(a, b=1):  # b has a default value of 1    return a + b
result = add(3, 4)  # 7
result2 = add(3)    # 4

8. Data Structures

1. List

my_list = [1, 2, 3, "apple", True]
my_list.append("banana")  # Add element
print(my_list[0])        # Access the first element

2. Tuple

my_tuple = (1, 2, "apple")  # Immutable
print(my_tuple[2])

3. Dictionary

my_dict = {"name": "Alice", "age": 25}
print(my_dict["name"])  # "Alice"
my_dict["city"] = "New York"  # Add key-value pair

4. Set

my_set = {1, 2, 3, 3}  # {1, 2, 3} - Automatically removes duplicates
my_set.add(4)

9. File Operations

1. Reading Files

with open("example.txt", "r") as file:    content = file.read()    print(content)

2. Writing Files

with open("output.txt", "w") as file:    file.write("Hello, File!")

10. Exception Handling

try:    x = 1 / 0
except ZeroDivisionError:    print("Cannot divide by zero!")
except Exception as e:    print(f"An error occurred: {e}")
finally:    print("This always executes")