How to Add a Key-Value Pair to a Map in Ruby - Step by Step Examples

How to Add a Key-Value Pair to a Map in Ruby ?

Answer

To add a key-value pair to a map in Ruby, you can use the subscript operator or the merge! method.

✐ Examples

1 Adding a Key-Value Pair Using Subscript Operator

We can add a key-value pair to a map in Ruby using the subscript operator, which adds an element with a specific key and value to the map.

For example,

We start by declaring and initializing a hash named my_map with some key-value pairs. In this example, the hash has string keys and integer values.
We use the subscript operator to add a new key-value pair to the hash. The subscript operator allows us to specify the key and assign a value to it.
We print the updated hash to the console using the puts function.

Ruby Program

my_map = {
    'one' => 1,
    'two' => 2,
    'three' => 3
}

# Add a key-value pair using subscript operator
my_map['four'] = 4

# Print the updated hash
puts my_map

Output

{'one' => 1, 'two' => 2, 'three' => 3, 'four' => 4}

2 Adding Multiple Key-Value Pairs Using merge! Method

We can add multiple key-value pairs to a map in Ruby using the merge! method, which adds all key-value pairs from another hash.

For example,

We start by declaring and initializing a hash named my_map with some key-value pairs. In this example, the hash has string keys and integer values.
We use the merge! method to add multiple new key-value pairs to the hash. The merge! method takes another hash containing the key-value pairs to be added.
We print the updated hash to the console using the puts function.

Ruby Program

my_map = {
    'one' => 1,
    'two' => 2,
    'three' => 3
}

# Add multiple key-value pairs using merge! method
my_map.merge!({'four' => 4, 'five' => 5})

# Print the updated hash
puts my_map

Output

{'one' => 1, 'two' => 2, 'three' => 3, 'four' => 4, 'five' => 5}

3 Adding a Key-Value Pair Conditionally Using store Method

We can add a key-value pair to a map in Ruby using the store method, which adds the key-value pair if the key does not already exist.

For example,

We start by declaring and initializing a hash named my_map with some key-value pairs. In this example, the hash has string keys and integer values.
We use the store method to add a new key-value pair to the hash. The store method takes two arguments: the key and the value to be added.
We print the updated hash to the console using the puts function.

Ruby Program

my_map = {
    'one' => 1,
    'two' => 2,
    'three' => 3
}

# Add a key-value pair using store method
my_map.store('four', 4)

# Print the updated hash
puts my_map

Output

{'one' => 1, 'two' => 2, 'three' => 3, 'four' => 4}

Summary

In this tutorial, we learned How to Add a Key-Value Pair to a Map in Ruby language with well detailed examples.

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How to Add a Key-Value Pair to a Map in Ruby - Step by Step Examples