Python Convert Array to Dictionary

1. Introduction

In Python, arrays are collections of items stored at contiguous memory locations which allow us to store multiple items of the same type together. Sometimes we might need to convert these arrays into dictionaries to map each element to a particular identifier. This blog post will explore how to transform an array into a dictionary, which can be useful for when you need a lookup table that maps array indices to array elements.

Definition

Converting an array to a dictionary in Python involves creating a dictionary with keys representing the index (or another identifier) and values representing the elements of the array. This can be done by iterating over the array and constructing a new dictionary or using a dictionary comprehension.

2. Program Steps

1. Import the array module to work with arrays.

2. Initialize an array with the desired elements.

3. Create a dictionary where each array element is mapped to its corresponding index.

4. Use a for loop or dictionary comprehension to populate the dictionary.

5. Output the new dictionary.

3. Code Program

# Step 1: Import the array module
import array

# Step 2: Initialize an array with elements
num_array = array.array('i', [10, 20, 30, 40, 50])

# Step 3: Create an empty dictionary to hold the array elements
array_dict = {}

# Step 4: Populate the dictionary with array elements using a for loop
for index, element in enumerate(num_array):
    array_dict[index] = element

# Alternatively, use dictionary comprehension
# array_dict = {index: element for index, element in enumerate(num_array)}

# Step 5: Print the new dictionary
print(array_dict)

Output:

{0: 10, 1: 20, 2: 30, 3: 40, 4: 50}

Explanation:

1. The array module is imported to allow the creation of an array with type 'i' for integers.

2. num_array is an array of integers that we wish to convert to a dictionary.

3. array_dict is initialized as an empty dictionary that will eventually store our array elements.

4. A for loop uses enumerate(num_array), which provides a counter (index) and the value (element) for each element in the array, and adds them to array_dict as key-value pairs.

5. The print function outputs array_dict, which shows a dictionary representation of num_array where the keys are the indices of elements in the original array.