How to Convert an Array of Key-Value Pairs to a Map in Ruby

How to Convert an Array of Key-Value Pairs to a Map in Ruby ?

Answer

To convert an array of key-value pairs to a hash in Ruby, you can use the `to_h` method, which creates a hash from a collection of key-value pairs.

✐ Examples

1 Converting an Array of Arrays to a Hash

We can convert an array of key-value pairs to a hash in Ruby using the `to_h` method, which directly converts an array of pairs to a hash.

For example,

We start by declaring and initializing an array of key-value pairs named pairs. In this example, the pairs are represented as arrays with two elements: a key and a value.
We convert the array of pairs to a hash using the to_h method.
We print the resulting hash to the console using the puts method to verify the conversion.

Ruby Program

pairs = [
    [1, 10],
    [2, 20],
    [3, 30],
    [4, 40],
    [5, 50]
]

# Convert the array of pairs to a hash
my_hash = pairs.to_h

# Print the resulting hash
puts 'Hash from array of pairs:'
my_hash.each do |key, value|
  puts "#{key}: #{value}"
end

Output

Hash from array of pairs:
1: 10
2: 20
3: 30
4: 40
5: 50

2 Converting an Array of Objects to a Hash

We can convert an array of objects with key and value properties to a hash in Ruby by iterating over the array and adding each object's key-value pair to the hash.

For example,

We start by declaring and initializing an array of objects named pairs. In this example, each object is a hash with :key and :value properties.
We create an empty hash named my_hash to store the key-value pairs.
We iterate over the array using the each method and add each object's key-value pair to the hash.
We print the resulting hash to the console using the puts method to verify the conversion.

Ruby Program

pairs = [
    { key: 1, value: 10 },
    { key: 2, value: 20 },
    { key: 3, value: 30 },
    { key: 4, value: 40 },
    { key: 5, value: 50 }
]

# Create an empty hash to store the key-value pairs
my_hash = {}

# Iterate over the array and add each object's key-value pair to the hash
pairs.each do |pair|
  my_hash[pair[:key]] = pair[:value]
end

# Print the resulting hash
puts 'Hash from array of objects:'
my_hash.each do |key, value|
  puts "#{key}: #{value}"
end

Output

Hash from array of objects:
1: 10
2: 20
3: 30
4: 40
5: 50

3 Converting a List of Pairs to a Hash

We can convert a list of key-value pairs to a hash in Ruby using the `to_h` method, which directly converts a list of pairs to a hash.

For example,

We start by declaring and initializing a list of key-value pairs named pairs. In this example, the pairs are represented as arrays with two elements: a key and a value.
We convert the list of pairs to a hash using the to_h method.
We print the resulting hash to the console using the puts method to verify the conversion.

Ruby Program

pairs = [
    [1, 10],
    [2, 20],
    [3, 30],
    [4, 40],
    [5, 50]
]

# Convert the list of pairs to a hash
my_hash = pairs.to_h

# Print the resulting hash
puts 'Hash from list of pairs:'
my_hash.each do |key, value|
  puts "#{key}: #{value}"
end

Output

Hash from list of pairs:
1: 10
2: 20
3: 30
4: 40
5: 50

Summary

In this tutorial, we learned How to Convert an Array of Key-Value Pairs to a Map in Ruby language with well detailed examples.

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How to Convert an Array of Key-Value Pairs to a Map in Ruby