Ruby Convert List to Map

1. Introduction

In Ruby, 'map' is a term often associated with the map method used for transforming the elements of an array or a list. However, 'map' in other programming contexts might refer to a dictionary or a hash. Since Ruby uses 'hash' for this data structure, this blog post will cover how to convert a list (an array in Ruby) into a hash, which could be referred to as 'mapping' a list to a hash.

In Ruby, a 'map' can be considered a collection of key-value pairs, similar to a hash. The process involves taking an array and constructing a hash such that each element of the array is associated with a key or a value. This is useful when you need quick lookups or want to uniquely identify elements in an array.

2. Program Steps

1. Define the list (array) that needs to be converted to a map (hash).

2. Determine how the array elements will be used as keys and values in the hash.

3. Convert the array to a hash.

4. Output the hash.

3. Code Program

# Step 1: Define the list (array) to be converted
list = ['apple', 'banana', 'orange']
# Step 2: Determine how array elements will be keys or values
# In this example, the keys will be the index of each element
# Step 3: Convert the array to a hash
hash_map = list.each_with_index.to_h { |item, index| [index, item] }
# hash_map is now a hash where the keys are indices and the values are the elements from the array


{0 => "apple", 1 => "banana", 2 => "orange"}


1. list is an array of strings representing fruits.

2. The structure for the hash is decided: each element's index in the array will serve as its key in the hash.

3. list.each_with_index.to_h converts the array to a hash. The block provided to to_h specifies that each element and its index should be inserted into the hash as a key-value pair.

4. hash_map contains the hash generated from the list, with indices as keys and fruit names as values.