You can easily create your own modules. All you need to do is save your Python code in a .py file. Later, you can import and use this module in other programs.

def add(a, b):
    return a + b

def subtract(a, b):
    return a - b

import math_tools

print(math_tools.add(3, 5))  # Output: 8
print(math_tools.subtract(10, 4))  # Output: 6

Importing with Aliases: You can give an alias to a module or function while importing it to simplify the code or avoid naming conflicts.

import math as m

print(m.sqrt(25))  # Output: 5.0

Importing All Names from a Module: You can use the * symbol to import everything from a module

from math import *

print(sqrt(9))  # Output: 3.0

However, importing everything this way is discouraged as it can lead to confusion if you have multiple imports with the same function names.

A package is a collection of related modules. A package is just a directory that contains multiple Python files (modules) and an __init__.py file. The __init__.py file makes the directory a Python package.

math_package/
    __init__.py
    basic_operations.py
    advanced_operations.py

__init__.py: This file can be empty or contain initialization code for the package.

Modules (basic_operations.py, advanced_operations.py): The Python files inside the package contain your functions or classes.

my_package/
    __init__.py
    utilities.py

def greet(name):
    return f"Hello, {name}!"

from my_package import utilities

print(utilities.greet("Alice"))  # Output: Hello, Alice!

pip install package_name

pip install requests

import requests

response = requests.get("https://api.github.com")
print(response.status_code)  # Output: 200

import math

print(dir(math))  # Lists all functions and constants in the math module
help(math.sqrt)   # Provides documentation for the sqrt function

file = open("filename", "mode")

file = open("example.txt", "r")

file.close()

with open("example.txt", "r") as file:
    content = file.read()
    print(content)  # File is automatically closed after the block

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

with open("example.txt", "r") as file:
    line = file.readline()
    print(line)  # Prints the first line of the file

with open("example.txt", "r") as file:
    lines = file.readlines()
    print(lines)  # Prints all lines in a list

with open("output.txt", "w") as file:
    file.write("Hello, World!\n")
    file.write("This is a Python program.\n")

lines = ["First line\n", "Second line\n", "Third line\n"]

with open("output.txt", "w") as file:
    file.writelines(lines)

with open("output.txt", "a") as file:
    file.write("This line will be appended.\n")

with open("image.jpg", "rb") as file:
    binary_content = file.read()
    print(binary_content)  # Outputs the binary content of the image

with open("new_image.jpg", "wb") as file:
    file.write(binary_content)  # Writes binary content to a new file

try:
    with open("non_existent_file.txt", "r") as file:
        content = file.read()
except FileNotFoundError:
    print("File not found. Please check the filename.")

with open("example.txt", "r") as file:
    print(file.tell())  # Prints the current position of the file pointer
    file.seek(0)  # Moves the pointer to the beginning of the file
    print(file.read())

Write a Python program to count the number of words in a text file.

Write a Python program that copies the contents of one file into another file.

Write a Python program that reads the content of a file and writes it to a new file in reverse order

Write a Python program that opens a binary file (such as an image) and creates a copy of it.

Write a Python program that reads a text file and counts the frequency of each character in the file.

Welcome to Day 11 of the "Noob to Pro in Python" course! Today, we’ll focus on exceptions in Python, learning how to handle errors effectively. Exception handling is crucial for writing robust, error-free programs that behave predictably even when things go wrong. You’ll understand how to catch exceptions, raise errors, and use custom exceptions.

An exception is an event that occurs during the execution of a program that disrupts its normal flow. When a Python program encounters an error, it raises an exception, which terminates the program unless the error is handled.

try:
    # Code that might raise an exception
    risky_code()
except ExceptionType:
    # Code to handle the exception
    handle_exception()

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