How to Iterate Over Entries (Key-Value Pairs) in a Map in Ruby

How to Iterate Over Entries (Key-Value Pairs) in a Map in Ruby ?

Answer

To iterate over entries (key-value pairs) in a hash in Ruby, you can use the each method or a for loop. This allows you to access each key-value pair in the hash.

✐ Examples

1 Iterating Over Entries Using each Method

We can iterate over entries in a hash in Ruby using the each method, which provides a convenient syntax for iterating over all key-value pairs in the 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 each method to iterate over the key-value pairs in the hash.
In the block passed to each, we access each key and value.
We print each key and value to the console using the puts function to verify that we are iterating over all entries.

Ruby Program

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

# Iterate over entries using each method
my_map.each do |key, value|
  puts "Key: #{key}, Value: #{value}"
end

Output

Key: one, Value: 1
Key: two, Value: 2
Key: three, Value: 3

2 Iterating Over Entries Using for Loop

We can iterate over entries in a hash in Ruby using a for loop, which provides a flexible way to access each key-value pair in the 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 a for loop to iterate over the hash, accessing each key and value directly from the hash.
We print each key and value to the console using the puts function to verify that we are iterating over all entries.

Ruby Program

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

# Iterate over entries using for loop
for key, value in my_map do
  puts "Key: #{key}, Value: #{value}"
end

Output

Key: one, Value: 1
Key: two, Value: 2
Key: three, Value: 3

3 Storing and Iterating Over Entries Separately

We can store entries in a separate array and then iterate over the array in Ruby, which provides a way to work with key-value pairs independently of the 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 declare an array named entries to store the key-value pairs from the hash.
We use the to_a method to convert the hash to an array of key-value pairs and store it in the entries array.
We use a for loop to iterate over the entries array and print each key and value to the console using the puts function to verify that we have stored all entries separately.

Ruby Program

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

# Store entries in a separate array
entries = my_map.to_a

# Iterate over the entries array
for entry in entries do
  key, value = entry
  puts "Key: #{key}, Value: #{value}"
end

Output

Key: one, Value: 1
Key: two, Value: 2
Key: three, Value: 3

Summary

In this tutorial, we learned How to Iterate Over Entries (Key-Value Pairs) in a Map in Ruby language with well detailed examples.

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