How to Create a Map of Maps in Ruby - Step by Step Examples

How to Create a Map of Maps in Ruby ?

Answer

To create a map of maps in Ruby, you can use the Hash data structure. A map of maps allows you to organize data hierarchically, where each key in the outer hash points to another hash.

✐ Examples

1 Creating a Map of Maps with Integer Keys and Values

We can create a map of maps in Ruby by using the Hash data structure. This example demonstrates creating a hash where both the outer and inner hashes use integers for keys and values.

For example,

We start by declaring and initializing a hash named outer_hash where each value is another hash.
We populate the inner hashes with key-value pairs.
We insert the inner hashes into the outer hash using appropriate keys.
We print the resulting hash of hashes to the console to verify the structure.

Ruby Program

outer_hash = {}

# Populate the inner hashes
inner_hash1 = {1 => 10, 2 => 20, 3 => 30}
inner_hash2 = {4 => 40, 5 => 50, 6 => 60}

# Insert the inner hashes into the outer hash
outer_hash[1] = inner_hash1
outer_hash[2] = inner_hash2

# Print the resulting hash of hashes
puts 'Hash of hashes with integer keys and values:'
outer_hash.each do |outer_key, inner_hash|
  puts "Outer key: #{outer_key}"
  inner_hash.each do |inner_key, value|
    puts "  Inner key: #{inner_key}, value: #{value}"
  end
end

Output

Hash of hashes with integer keys and values:
Outer key: 1
  Inner key: 1, value: 10
  Inner key: 2, value: 20
  Inner key: 3, value: 30
Outer key: 2
  Inner key: 4, value: 40
  Inner key: 5, value: 50
  Inner key: 6, value: 60

2 Creating a Map of Maps with Mixed Key and Value Types

We can create a map of maps in Ruby by using the Hash data structure. This example demonstrates creating a hash where the outer hash uses strings for keys and the inner hashes use integers for keys and strings for values.

For example,

We start by declaring and initializing a hash named outer_hash where each value is another hash with mixed key and value types.
We populate the inner hashes with key-value pairs.
We insert the inner hashes into the outer hash using appropriate keys.
We print the resulting hash of hashes to the console to verify the structure.

Ruby Program

outer_hash = {}

# Populate the inner hashes
inner_hash1 = {1 => 'one', 2 => 'two', 3 => 'three'}
inner_hash2 = {4 => 'four', 5 => 'five', 6 => 'six'}

# Insert the inner hashes into the outer hash
outer_hash['first'] = inner_hash1
outer_hash['second'] = inner_hash2

# Print the resulting hash of hashes
puts 'Hash of hashes with mixed key and value types:'
outer_hash.each do |outer_key, inner_hash|
  puts "Outer key: #{outer_key}"
  inner_hash.each do |inner_key, value|
    puts "  Inner key: #{inner_key}, value: #{value}"
  end
end

Output

Hash of hashes with mixed key and value types:
Outer key: first
  Inner key: 1, value: one
  Inner key: 2, value: two
  Inner key: 3, value: three
Outer key: second
  Inner key: 4, value: four
  Inner key: 5, value: five
  Inner key: 6, value: six

3 Creating a Map of Maps with String Keys and Double Values

We can create a map of maps in Ruby by using the Hash data structure. This example demonstrates creating a hash where both the outer and inner hashes use strings for keys and floats for values.

For example,

We start by declaring and initializing a hash named outer_hash where each value is another hash with strings for keys and floats for values.
We populate the inner hashes with key-value pairs.
We insert the inner hashes into the outer hash using appropriate keys.
We print the resulting hash of hashes to the console to verify the structure.

Ruby Program

outer_hash = {}

# Populate the inner hashes
inner_hash1 = {'A' => 1.1, 'B' => 2.2, 'C' => 3.3}
inner_hash2 = {'D' => 4.4, 'E' => 5.5, 'F' => 6.6}

# Insert the inner hashes into the outer hash
outer_hash['group1'] = inner_hash1
outer_hash['group2'] = inner_hash2

# Print the resulting hash of hashes
puts 'Hash of hashes with string keys and float values:'
outer_hash.each do |outer_key, inner_hash|
  puts "Outer key: #{outer_key}"
  inner_hash.each do |inner_key, value|
    puts "  Inner key: #{inner_key}, value: #{value}"
  end
end

Output

Hash of hashes with string keys and float values:
Outer key: group1
  Inner key: A, value: 1.1
  Inner key: B, value: 2.2
  Inner key: C, value: 3.3
Outer key: group2
  Inner key: D, value: 4.4
  Inner key: E, value: 5.5
  Inner key: F, value: 6.6

Summary

In this tutorial, we learned How to Create a Map of Maps in Ruby language with well detailed examples.

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How to Create a Map of Maps in Ruby - Step by Step Examples