JSON library basics in Ruby - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the purpose of the JSON library in Ruby?

The JSON library in Ruby is used to convert Ruby objects into JSON strings and parse JSON strings back into Ruby objects.

beginner

How do you convert a Ruby hash to a JSON string?

Use JSON.generate(your_hash) or your_hash.to_json to convert a Ruby hash into a JSON string.

beginner

How do you parse a JSON string into a Ruby object?

Use JSON.parse(json_string) to convert a JSON string into a Ruby hash or array.

beginner

What Ruby module must you require to use JSON methods?

You must include require 'json' at the top of your Ruby file to use JSON methods.

intermediate

What is the difference between JSON.generate and JSON.dump?

JSON.generate returns a JSON string from a Ruby object. JSON.dump does the same but can also write the JSON string directly to an IO object like a file.

Which method converts a Ruby hash to a JSON string?

A JSON.read

B JSON.parse

C JSON.generate

D JSON.load

JSON.generate converts Ruby objects to JSON strings. JSON.parse does the opposite.

What must you do before using JSON methods in Ruby?

A require 'json'

B include JSON

C import 'json'

D use JSON.new

You must require 'json' to load the JSON library before using its methods.

Which method parses a JSON string into a Ruby object?

A JSON.generate

B JSON.write

C JSON.dump

D JSON.parse

JSON.parse converts JSON strings into Ruby hashes or arrays.

What does JSON.dump do that JSON.generate does not?

A Writes JSON directly to IO objects

B Parses JSON strings

C Converts JSON to XML

D Validates JSON syntax

JSON.dump can write JSON strings directly to files or other IO objects.

If you have a Ruby array, which method converts it to JSON?

A JSON.parse

B JSON.generate

C JSON.load

D JSON.read

JSON.generate works with arrays and hashes to create JSON strings.

Explain how to convert a Ruby hash to a JSON string and then back to a Ruby object.

Think about the methods to serialize and deserialize JSON.

Describe the difference between JSON.generate and JSON.dump in Ruby.

Consider where the JSON output goes.