Reading from a JSON file
In Ruby, we can easily read and write JSON files using the built-in JSON library.
Step 1: Make sure you have the JSON library installed. In case it is not, use the following command to install JSON:
gem install json
Step 2: Import the JSON library using the following command:
require ‘json’
Step 3: Read the file using the following command:
json_data = File.read(‘data.json’)
We’re using Ruby’s built-in File class to read the contents of a file. It reads the contents of the file specified and returns it as a string. In the context of JSON files, this line of code is typically used to read the JSON data from a file into a variable (json_data in this case), so that you can then parse and work with the JSON data in your Ruby program.
Step 4: Parse the given file into hash using the following line of code:
parsed_data = JSON.parse(json_data)
In this line we’re using the JSON.parse method to convert a JSON-formatted string (json_data) into a Ruby data structure.
- JSON: This is the module provided by the json library that we required earlier using require ‘json’. This module contains methods for working with JSON data in Ruby.
- parse: It takes a JSON-formatted string as input and converts it into an equivalent Ruby data structure. The resulting Ruby data structure could be a hash, an array, a string, a number, or nil, depending on the contents of the JSON string.
- json_data: This is the JSON-formatted string that we want to parse. It contains data encoded in the JSON format, which could have been read from a file, received from an API, or obtained from any other source.
- parsed_data: This is the variable where we’re storing the result of parsing the JSON data. After this line executes, parsed_data will hold a Ruby data structure representing the JSON data. You can then access and manipulate this data using Ruby’s built-in methods and constructs. For example, if the JSON data represents an object, parsed_data will be a hash in Ruby, allowing you to access its keys and values like any other hash.
Step 5: The inpect method is used to get a string representation stored in the variable ‘parsed_data’:
puts parsed_data.inspect
Code:
require 'json'
# Open and read the JSON file
file_path = 'data.json'
json_data = File.read(file_path)
# Parse the JSON data
parsed_data = JSON.parse(json_data)
# Now you can work with the parsed data
puts parsed_data.inspect
data.json:
{
“author”:”Stephen Hawking”,
“url”:”https://penguinrandomhouse.com/the-read-down/stephen-hawking/”,
“books”:
{
“1”:”A Brief History of Time”,
“2”:”The Grand Design”,
“3”: “How to Make a Spaceship”
}
}
Output:
{“author”=>”Stephen Hawking”, “url”=>”https://penguinrandomhouse.com/the-read-down/stephen-hawking/”, “books”=>{“1″=>”A Brief History of Time”, “2”=>”The Grand Design”, “3”=>”How to Make a Spaceship”}}
How to read/write JSON File?
Ruby is a dynamic, object-oriented programming language developed by Yukihiro Matsumoto in the mid-1990s. Its key features include a simple and elegant syntax, dynamic typing, object-oriented nature, support for mixins and modules, blocks and closures, metaprogramming, and a vibrant community with a rich ecosystem of libraries and frameworks. Ruby is popular for web development, automation scripts, and system administration tasks, and is primarily used through the Ruby on Rails web framework. It is also used for various other applications outside of web development.
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