Exercise

Python File Operations

These exercises are designed to help you practice working with file operations in Python. Follow each step carefully and try to predict the output before running the code.

Important: Be cautious when working with file operations, especially when deleting or overwriting files. Always make sure you're working in the correct directory and with the intended files.

File Organization

We'll add a new directory called file_operations to your existing file structure. The updated structure will look like this:

csf101-python_exercises/
│
├── basics/
│   ├── numbers.py
│   ├── strings.py
│   └── booleans.py
│
├── data_structures/
│   ├── lists.py
│   └── dictionaries.py
│
├── operators/
│   ├── arithmetic.py
│   ├── assignment.py
│   ├── comparison.py
│   ├── logical.py
│   └── bitwise.py
│
├── control_structures/
│   ├── conditionals.py
│   ├── loops.py
│   └── break_continue.py
│
├── functions_and_scope/
│   ├── basic_functions.py
│   ├── parameters_and_returns.py
│   ├── scope.py
│   └── recursion.py
│
└── file_operations/
    ├── text_files.py
    ├── binary_files.py
    └── file_management.py

Create a new directory called file_operations inside your csf101-python_exercises directory.

Exercise 1: Working with Text Files

File: file_operations/text_files.py

Create a new file called text_files.py in the file_operations directory and complete the following exercises in this file.

Write a function that creates a new text file and writes a few lines to it.

def create_and_write_file(filename):
    with open(filename, 'w') as file:
        file.write("This is the first line.\n")
        file.write("This is the second line.\n")
        file.write("This is the third line.\n")

create_and_write_file('sample.txt')
print("File created and written successfully.")

Write a function that reads and prints the contents of the file you just created.

def read_and_print_file(filename):
    with open(filename, 'r') as file:
        content = file.read()
        print(content)

read_and_print_file('sample.txt')

Write a function that appends a new line to an existing file.

def append_to_file(filename, new_line):
    with open(filename, 'a') as file:
        file.write(new_line + "\n")

append_to_file('sample.txt', "This is an appended line.")
print("Line appended successfully.")
read_and_print_file('sample.txt')  # Verify the appended line

Write a function that reads a file line by line and prints each line with its line number.

def print_lines_with_numbers(filename):
    with open(filename, 'r') as file:
        for index, line in enumerate(file, start=1):
            print(f"{index}: {line.strip()}")

print_lines_with_numbers('sample.txt')

Write a function that counts the number of words in a text file.

def count_words(filename):
    with open(filename, 'r') as file:
        content = file.read()
        words = content.split()
        return len(words)

word_count = count_words('sample.txt')
print(f"The file contains {word_count} words.")

Exercise 2: Working with Binary Files

File: file_operations/binary_files.py

Create a new file called binary_files.py in the file_operations directory and complete the following exercises in this file.

Write a function that creates a binary file containing some bytes.

def create_binary_file(filename):
    data = bytes([0, 1, 2, 3, 4, 5])
    with open(filename, 'wb') as file:
        file.write(data)

create_binary_file('binary_sample.bin')
print("Binary file created successfully.")

Write a function that reads and prints the contents of the binary file as bytes.

def read_binary_file(filename):
    with open(filename, 'rb') as file:
        content = file.read()
        print("Binary content:", content)

read_binary_file('binary_sample.bin')

Write a function that appends bytes to an existing binary file.

def append_to_binary_file(filename, data):
    with open(filename, 'ab') as file:
        file.write(data)

append_to_binary_file('binary_sample.bin', bytes([6, 7, 8, 9]))
print("Bytes appended to binary file.")
read_binary_file('binary_sample.bin')  # Verify the appended bytes

Exercise 3: File Management

File: file_operations/file_management.py

Create a new file called file_management.py in the file_operations directory and complete the following exercises in this file.

Write a function that checks if a file exists.

import os

def file_exists(filename):
    return os.path.exists(filename)

print(f"'sample.txt' exists: {file_exists('sample.txt')}")
print(f"'nonexistent.txt' exists: {file_exists('nonexistent.txt')}")

Write a function that renames a file.

import os

def rename_file(old_name, new_name):
    os.rename(old_name, new_name)

rename_file('sample.txt', 'renamed_sample.txt')
print("File renamed successfully.")
print(f"'renamed_sample.txt' exists: {file_exists('renamed_sample.txt')}")

Write a function that deletes a file.

import os

def delete_file(filename):
    if os.path.exists(filename):
        os.remove(filename)
        print(f"{filename} has been deleted.")
    else:
        print(f"{filename} does not exist.")

delete_file('binary_sample.bin')

Write a function that creates a new directory.

import os

def create_directory(directory_name):
    if not os.path.exists(directory_name):
        os.makedirs(directory_name)
        print(f"Directory '{directory_name}' created successfully.")
    else:
        print(f"Directory '{directory_name}' already exists.")

create_directory('new_folder')

Write a function that lists all files in a directory.

import os

def list_files(directory):
    files = os.listdir(directory)
    for file in files:
        print(file)

print("Files in the current directory:")
list_files('.')

Write a function that copies a file from one location to another.

import shutil

def copy_file(source, destination):
    shutil.copy2(source, destination)
    print(f"File copied from {source} to {destination}")

copy_file('renamed_sample.txt', 'new_folder/copied_sample.txt')

Write a function that reads a CSV file and prints its contents.

import csv

def read_csv_file(filename):
    with open(filename, 'r', newline='') as file:
        csv_reader = csv.reader(file)
        for row in csv_reader:
            print(', '.join(row))

# First, create a sample CSV file
with open('sample.csv', 'w', newline='') as file:
    csv_writer = csv.writer(file)
    csv_writer.writerow(['Name', 'Age', 'City'])
    csv_writer.writerow(['Alice', '30', 'New York'])
    csv_writer.writerow(['Bob', '25', 'Los Angeles'])

print("Contents of sample.csv:")
read_csv_file('sample.csv')

Congratulations!

Remember to run each file separately to see the output of your exercises. You can do this by navigating to the appropriate directory in your terminal and running python filename.py (e.g., python text_files.py).

Important: Be cautious when working with file operations, especially when deleting or overwriting files. Always make sure you're working in the correct directory and with the intended files.