File Handling: Practice Problems

The best way to master file handling is by solving real-world problems. This section provides a set of exercises designed to test your understanding of reading, writing, and manipulating different file types. Each problem includes a solution for you to check your work.

Text File Problems

Problem 1: Word and Line Counter

Task: Write a function analyze_text_file(filepath) that takes a file path, reads the file, and returns a dictionary containing the number of lines, words, and characters in the file.

PygroundTry It Out

Create a file named `story.txt` and analyze it using your function.

Expected Output:

{'lines': 2, 'words': 17, 'characters': 83}

Output:

Problem 2: Find and Replace

Task: Write a program that reads a file, replaces all occurrences of a specific word with another word, and writes the result to a new file.

PygroundTry It Out

In `story.txt`, replace every instance of 'fox' with 'cat' and save the output to `story_revised.txt`.

Expected Output:

File 'story_revised.txt' created successfully.

--- Revised Content ---
The quick brown cat jumps over the lazy dog.
This is the second line of the story.

Output:

Problem 3: Numbered Lines

Task: Read a source file and write its content to a new file, adding line numbers at the beginning of each line.

PygroundTry It Out

Read `story.txt` and write its content with line numbers to `story_numbered.txt`.

Expected Output:

File 'story_numbered.txt' created successfully.

Output:

CSV File Problems

Problem 4: Create a Student Roster CSV

Task: Create a CSV file named students.csv to store student data (StudentID, Name, Major). Write a header and at least three rows of data using the csv module.

PygroundTry It Out

Generate `students.csv` with data for three students.

Expected Output:

students.csv created successfully.

Output:

Problem 5: Filter a CSV File

Task: Read the students.csv file you just created and print the names of all students who are majoring in “Computer Science”.

PygroundTry It Out

Filter `students.csv` and display the names of Computer Science majors.

Expected Output:

Computer Science Majors:
- Alice

Output:

JSON File Problems

Problem 6: Create a JSON Configuration File

Task: Create a JSON file named app_config.json that stores configuration settings for an application, including a window size, theme, and a list of enabled plugins. Use an indent for readability.

PygroundTry It Out

Generate `app_config.json` with pretty-printing.

Expected Output:

app_config.json created successfully with indentation.

Output:

Problem 7: Read and Modify JSON Data

Task: Read the app_config.json file, change the theme from “dark” to “light”, add a new plugin called “file-explorer”, and save the changes back to the same file.

PygroundTry It Out

Load `app_config.json`, update its data, and overwrite the file.

Expected Output:

Original theme: dark
Updated theme: light
app_config.json has been updated.