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Ruby Hashes

In Ruby, a hash is a collection of key-value pairs, similar to a dictionary in Python or an object in JavaScript. In this article, we'll take a look at how to define and use hashes in Ruby.

Syntax

A hash in Ruby is defined using curly braces {}. Keys and values are separated by a colon : and each key-value pair is separated by a comma ,.

hash = { key1: value1, key2: value2, key3: value3 }

The keys can be any object, but typically they are symbols or strings. The values can be any data type in Ruby.

Example

# Define a hash
person = { name: "John Doe", age: 25, occupation: "Software Engineer" }

# Access the values
puts person[:name]
puts person[:age]
puts person[:occupation]

Output

John Doe
25
Software Engineer

Explanation

In the example above, we define a hash called person with three key-value pairs. We access the values of the name, age, and occupation keys using the [] operator and output them to the console.

Use

Hashes are commonly used in Ruby for storing and retrieving related data. They are similar to arrays, but instead of accessing values by index, you access them by key.

# Define a hash
countries = { usa: "United States", ind: "India", aus: "Australia" }

# Loop through the keys and values
countries.each do |key, value|
  puts "#{key} is short for #{value}"
end

Output

usa is short for United States
ind is short for India
aus is short for Australia

In the example above, we define a hash called countries with three key-value pairs. We then loop through the keys and values using the each method and output a string that combines the key and value for each pair.

Important Points

  • A hash is a collection of key-value pairs in Ruby.
  • Hashes are defined using curly braces {}.
  • Keys and values are separated by a colon : and each key-value pair is separated by a comma ,.
  • Keys can be any object, but typically they are symbols or strings.
  • Values can be any data type in Ruby.
  • Hashes are commonly used for storing related data and retrieving it by key.

Summary

Hashes are a powerful data structure in Ruby that allow you to store and retrieve related data using key-value pairs. They are similar to dictionaries in other languages and provide a flexible way of organizing and accessing data. Understanding how to define, access, and manipulate hashes is an important skill for any Ruby programmer.

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