1. File Handling in Python

Opening and Closing Files

Python uses the open() function to handle files.

File Modes

Basic File Operations

                                        # Basic file writing
                                        file = open("sample.txt", "w")  # Open for writing
                                        file.write("Hello, Python!")
                                        file.close()  # Always close to save changes

                                        # Safer method using 'with'
                                        with open("sample.txt", "r") as file:
                                            content = file.read()
                                            print(content)

Reading and Writing Files

                                        # Writing multiple lines
                                        with open("greet.txt", "w") as f:
                                            f.write("Good morning!\n")
                                            f.write("Welcome to Python.")

                                        # Reading entire file
                                        with open("greet.txt", "r") as f:
                                            print(f.read())

                                        # Reading line by line
                                        with open("greet.txt", "r") as f:
                                            for line in f:
                                                print(line.strip())

Appending to Files

                                        with open("greet.txt", "a") as f:
                                            f.write("\nHave a great day!")

Binary Files

                                        # Writing binary data
                                        with open("binary_file.dat", "wb") as f:
                                            f.write(b"This is binary data")
                                        
                                        # Reading binary data
                                        with open("binary_file.dat", "rb") as f:
                                            print(f.read())

2. Data Serialization

JSON (JavaScript Object Notation)

                                        import json
                                        
                                        # Writing JSON
                                        data = {"name": "Emmanuel", "age": 22}
                                        with open("data.json", "w") as f:
                                            json.dump(data, f)
                                        
                                        # Reading JSON
                                        with open("data.json", "r") as f:
                                            person = json.load(f)
                                            print(person["name"])

CSV (Comma-Separated Values)

                                        import csv
                                        
                                        # Writing CSV
                                        rows = [["Name", "Age"], ["Emmanuel", 22], ["John", 30]]
                                        with open("people.csv", "w", newline="") as f:
                                            writer = csv.writer(f)
                                            writer.writerows(rows)
                                        
                                        # Reading CSV
                                        with open("people.csv", "r") as f:
                                            reader = csv.reader(f)
                                            for row in reader:
                                                print(row)

Pickle (Python Object Serialization)

                                        import pickle
                                        
                                        # Saving data
                                        data = {"name": "Emmanuel", "skills": ["Python", "Flutter"]}
                                        with open("data.pkl", "wb") as f:
                                            pickle.dump(data, f)
                                        
                                        # Loading data
                                        with open("data.pkl", "rb") as f:
                                            obj = pickle.load(f)
                                            print(obj["skills"])

3. Working with Directories

                                        import os
                                        
                                        # Create directory
                                        os.mkdir("test_folder")
                                        
                                        # Rename directory
                                        os.rename("test_folder", "renamed_folder")
                                        
                                        # Remove directory
                                        os.rmdir("renamed_folder")
                                        
                                        # List files
                                        print("Files in current directory:")
                                        for file in os.listdir("."):
                                            print(file)
                                        
                                        # Check existence
                                        print("\nFile checks:")
                                        print(os.path.exists("data.json"))  # True/False
                                        print(os.path.isfile("data.json"))  # True if file
                                        print(os.path.isdir("my_folder"))  # True if directory

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