How to Update the Value for a Key in a Map in Ruby - Step by Step Examples

How to Update the Value for a Key in a Map in Ruby ?

Answer

To update the value for a key in a hash in Ruby, you can use the subscript operator or the store method. These methods allow you to modify the value associated with a specific key directly.

✐ Examples

1 Updating the Value Using Subscript Operator

We can update the value for a key in a hash in Ruby using the subscript operator, which allows us to modify the value associated with a specific key directly.

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 update the value for a specific key in the hash. The subscript operator allows us to assign a new value to the key.
We print the updated hash to the console using the puts function.

Ruby Program

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

# Update the value using subscript operator
my_map['two'] = 22

# Print the updated hash
puts my_map

Output

{'one' => 1, 'two' => 22, 'three' => 3}

2 Updating the Value Using store Method

We can update the value for a key in a hash in Ruby using the store method, which allows us to modify the value associated with a specific key directly.

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 update the value for a specific key in the hash. The store method takes the key and the new value to be assigned.
We print the updated hash to the console using the puts function.

Ruby Program

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

# Update the value using store method
my_map.store('two', 22)

# Print the updated hash
puts my_map

Output

{'one' => 1, 'two' => 22, 'three' => 3}

3 Updating the Value Conditionally Using fetch Method

We can update the value for a key in a hash in Ruby using the fetch method to conditionally update the value if the key exists.

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 fetch method to check if the key exists in the hash. If the key exists, we update the value using the subscript operator.
We print the updated hash to the console using the puts function.

Ruby Program

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

# Update the value conditionally using fetch method
my_map['two'] = my_map.fetch('two', 22)

# Print the updated hash
puts my_map

Output

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

Summary

In this tutorial, we learned How to Update the Value for a Key in a Map in Ruby language with well detailed examples.

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How to Update the Value for a Key in a Map in Ruby - Step by Step Examples