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File & Data Management Quiz

Test your knowledge of Ruby's file I/O operations, CSV/JSON/YAML processing, environment variables, and marshalling. This comprehensive quiz covers practical scenarios and best practices you'll encounter in real-world Ruby development.

Quiz Progress

25 Questions | ~15 minutes

Complete all questions to see your results and detailed explanations.

File I/O Operations (8 questions)

1. What's the safest way to read a file in Ruby?

file = File.open("data.txt"); content = file.read; file.close File.open("data.txt") { |file| file.read } File.read("data.txt") Both B and C are safe, but B is preferred for large files

2. Which file mode should you use to append data to an existing file?

"w" (write mode) "a" (append mode) "r+" (read/write mode) "w+" (write/read mode)

3. What does `File.exist?("path/to/file")` return if the path exists but is a directory?

true false :directory Raises an exception

4. Which Pathname method returns the file extension?

extname extension ext suffix

5. What's the most memory-efficient way to process a very large file line by line?

File.readlines("file.txt").each { |line| process(line) } File.foreach("file.txt") { |line| process(line) } File.read("file.txt").split("\n").each { |line| process(line) } All methods use the same amount of memory

6. How do you create nested directories safely in Ruby?

Dir.mkdir("path/to/nested/dir") FileUtils.mkdir_p("path/to/nested/dir") File.makedirs("path/to/nested/dir") Dir.create_nested("path/to/nested/dir")

7. What happens if you try to write to a file without proper permissions?

The operation silently fails Errno::EACCES exception is raised Ruby creates the file with default permissions The system prompts for administrator access

8. What's the difference between `puts` and `write` when writing to a file?

They're identical in functionality puts adds a newline, write doesn't write is faster than puts puts only works with strings

CSV, JSON & YAML Processing (6 questions)

9. How do you read a CSV file with headers and access columns by name?

CSV.foreach("file.csv", headers: true) { |row| puts row["name"] } CSV.read("file.csv").each { |row| puts row[:name] } CSV.parse("file.csv", headers: true) { |row| puts row[0] } CSV.open("file.csv").headers["name"]

10. What's the difference between `JSON.parse` and `JSON.parse(str, symbolize_names: true)`?

No difference in functionality The second creates hash keys as symbols instead of strings The second is faster but uses more memory The second validates the JSON structure

11. Which YAML loading method is safer for untrusted input?

YAML.load(yaml_string) YAML.safe_load(yaml_string) YAML.load_file(yaml_file) All methods are equally safe

12. What's the main advantage of CSV over JSON for tabular data?

CSV files are smaller in size CSV is human-readable and Excel-compatible CSV parsing is faster than JSON CSV supports more data types

13. How do you generate pretty-formatted JSON output?

JSON.generate(data, pretty: true) JSON.pretty_generate(data) JSON.format(data) data.to_json(format: :pretty)

14. What happens when you try to parse invalid JSON with `JSON.parse`?

Returns nil Returns an empty hash Raises JSON::ParserError Fixes the JSON automatically

Environment Variables (6 questions)

15. What's the difference between `ENV["VAR"]` and `ENV.fetch("VAR")`?

They're identical in functionality ENV["VAR"] returns nil if missing, ENV.fetch("VAR") raises KeyError fetch is case-insensitive fetch converts values to proper types

16. How do you convert an environment variable string to a boolean in Ruby?

ENV["DEBUG"].to_bool ENV["DEBUG"] == "true" Boolean(ENV["DEBUG"]) ENV["DEBUG"].present?

17. What should you add to your .gitignore file when using .env files?

.env .env* .env.local Nothing, .env files should be committed

18. How do you temporarily set environment variables for a single command in Unix/Linux?

export VAR=value && ruby script.rb VAR=value ruby script.rb set VAR=value; ruby script.rb ruby script.rb --env VAR=value

19. What's the recommended way to provide default values for environment variables?

ENV["PORT"] || 3000 ENV.fetch("PORT", 3000) ENV["PORT"] ? ENV["PORT"] : 3000 All approaches are equivalent

20. What's the primary benefit of using environment variables over hardcoded configuration?

Faster application startup Better performance Environment-specific configuration without code changes Automatic data validation

Marshalling & Serialization (5 questions)

21. What's the primary security risk with `Marshal.load`?

Data corruption Arbitrary code execution Memory leaks Slow performance

22. Which objects CANNOT be marshalled by default?

Strings and numbers Arrays and hashes Procs, lambdas, and File objects Custom class instances

23. What's the purpose of implementing `marshal_dump` and `marshal_load` methods?

Improve marshalling performance Custom control over what data gets serialized Enable marshalling of previously unmarshalable objects Debug marshalling issues

24. Which is the safest alternative to Marshal for external data?

Binary Marshal format JSON with proper validation YAML.load with any input Base64 encoded Marshal data

25. What's a practical use case for deep cloning with Marshal?

Sending data over the network Creating independent copies of complex objects Persisting data to a database Logging application state

File & Data Management Quiz

File & Data Management Quiz

Quiz Progress

File I/O Operations (8 questions)

1. What's the safest way to read a file in Ruby?

2. Which file mode should you use to append data to an existing file?

3. What does `File.exist?("path/to/file")` return if the path exists but is a directory?

4. Which Pathname method returns the file extension?

5. What's the most memory-efficient way to process a very large file line by line?

6. How do you create nested directories safely in Ruby?

7. What happens if you try to write to a file without proper permissions?

8. What's the difference between `puts` and `write` when writing to a file?

CSV, JSON & YAML Processing (6 questions)

9. How do you read a CSV file with headers and access columns by name?

10. What's the difference between `JSON.parse` and `JSON.parse(str, symbolize_names: true)`?

11. Which YAML loading method is safer for untrusted input?

12. What's the main advantage of CSV over JSON for tabular data?

13. How do you generate pretty-formatted JSON output?

14. What happens when you try to parse invalid JSON with `JSON.parse`?

Environment Variables (6 questions)

15. What's the difference between `ENV["VAR"]` and `ENV.fetch("VAR")`?

16. How do you convert an environment variable string to a boolean in Ruby?

17. What should you add to your .gitignore file when using .env files?

18. How do you temporarily set environment variables for a single command in Unix/Linux?

19. What's the recommended way to provide default values for environment variables?

20. What's the primary benefit of using environment variables over hardcoded configuration?

Marshalling & Serialization (5 questions)

21. What's the primary security risk with `Marshal.load`?

22. Which objects CANNOT be marshalled by default?

23. What's the purpose of implementing `marshal_dump` and `marshal_load` methods?

24. Which is the safest alternative to Marshal for external data?

25. What's a practical use case for deep cloning with Marshal?

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File & Data Management Quiz

File & Data Management Quiz

Quiz Progress

File I/O Operations (8 questions)

1. What's the safest way to read a file in Ruby?

2. Which file mode should you use to append data to an existing file?

3. What does File.exist?("path/to/file") return if the path exists but is a directory?

4. Which Pathname method returns the file extension?

5. What's the most memory-efficient way to process a very large file line by line?

6. How do you create nested directories safely in Ruby?

7. What happens if you try to write to a file without proper permissions?

8. What's the difference between puts and write when writing to a file?

CSV, JSON & YAML Processing (6 questions)

9. How do you read a CSV file with headers and access columns by name?

10. What's the difference between JSON.parse and JSON.parse(str, symbolize_names: true)?

11. Which YAML loading method is safer for untrusted input?

12. What's the main advantage of CSV over JSON for tabular data?

13. How do you generate pretty-formatted JSON output?

14. What happens when you try to parse invalid JSON with JSON.parse?

Environment Variables (6 questions)

15. What's the difference between ENV["VAR"] and ENV.fetch("VAR")?

16. How do you convert an environment variable string to a boolean in Ruby?

17. What should you add to your .gitignore file when using .env files?

18. How do you temporarily set environment variables for a single command in Unix/Linux?

19. What's the recommended way to provide default values for environment variables?

20. What's the primary benefit of using environment variables over hardcoded configuration?

Marshalling & Serialization (5 questions)

21. What's the primary security risk with Marshal.load?

22. Which objects CANNOT be marshalled by default?

23. What's the purpose of implementing marshal_dump and marshal_load methods?

24. Which is the safest alternative to Marshal for external data?

25. What's a practical use case for deep cloning with Marshal?

Quiz Results

Quick Navigation

Related Topics

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3. What does `File.exist?("path/to/file")` return if the path exists but is a directory?

8. What's the difference between `puts` and `write` when writing to a file?

10. What's the difference between `JSON.parse` and `JSON.parse(str, symbolize_names: true)`?

14. What happens when you try to parse invalid JSON with `JSON.parse`?

15. What's the difference between `ENV["VAR"]` and `ENV.fetch("VAR")`?

21. What's the primary security risk with `Marshal.load`?

23. What's the purpose of implementing `marshal_dump` and `marshal_load` methods?