2025 Python Arrays

Introduction

Arrays in Python are used to store multiple values of the same data type in a structured way. They are more memory-efficient than lists for handling large numerical data.

The array module in Python provides various methods to manipulate arrays, such as adding, removing, searching, and modifying elements. Understanding these methods helps in efficient data handling and processing.

Python Arrays

Introduction

Arrays in Python are used to store multiple values of the same data type in a single variable. They provide a structured way to handle large amounts of data efficiently. Unlike lists, arrays in Python require elements to be of a fixed type. While Python does not have a built-in array data type, the array module allows us to create and manipulate arrays.

This guide will cover everything about Python arrays, including their creation, modification, looping, and comparison with lists, along with FAQs for a deeper understanding.

1. Creating an Array in Python

To use arrays in Python, we must first import the array module:

import array  

# Creating an array of integers
numbers = array.array('i', [10, 20, 30, 40, 50])  

print(numbers)  # Output: array('i', [10, 20, 30, 40, 50])

Explanation:

• 'i' → Type code representing integer values.
• [10, 20, 30, 40, 50] → The actual elements of the array.

Common Type Codes Used in Arrays

Type Code	Data Type
'i'	Integer
'f'	Float
'd'	Double (Large float)
'b'	Signed Byte
'u'	Unicode Character

2. Accessing Elements in an Array

You can access array elements using indexing, just like in lists.

print(numbers[0])  # Output: 10
print(numbers[2])  # Output: 30

Negative indexing also works:

print(numbers[-1])  # Output: 50 (Last element)

3. Modifying an Array

Python allows modification of elements in an array by referencing their index.

a) Changing an Element

numbers[1] = 25  
print(numbers)  # Output: array('i', [10, 25, 30, 40, 50])

b) Adding Elements

• append(value) → Adds an element at the end.
• insert(index, value) → Inserts an element at a specific position.

numbers.append(60)  # Adds 60 at the end
numbers.insert(2, 35)  # Inserts 35 at index 2

print(numbers)  # Output: array('i', [10, 25, 35, 30, 40, 50, 60])

4. Removing Elements from an Array

To delete elements, use:

• remove(value) → Removes the first occurrence of the given value.
• pop(index) → Removes an element at a specific index (default is last element).

numbers.remove(25)  # Removes 25 from the array
numbers.pop(3)  # Removes the element at index 3

print(numbers)  # Output: array('i', [10, 35, 30, 50, 60])

5. Looping Through an Array

Using a for loop

for num in numbers:
    print(num)

Output:

10  
35  
30  
50  
60  

Using a while loop

i = 0
while i < len(numbers):
    print(numbers[i])
    i += 1

6. Finding the Length of an Array

Use len() to get the number of elements in an array.

print(len(numbers))  # Output: 5

7. Difference Between Lists and Arrays in Python

Feature	Lists	Arrays
Data Type	Can store mixed data types	Requires elements of the same type
Performance	Slower for numerical operations	Faster for numerical operations
Import Required?	No, lists are built-in	Yes, import array is needed
Best for	General-purpose use	Numerical and memory-efficient operations

Accessing Elements of an Array in Python

Introduction

An array stores multiple values in a single variable. Each value in an array has a unique index that helps in accessing it. In Python, you can retrieve, modify, and work with array elements using their index values.

Python does not have a built-in array type, but the array module allows us to create arrays that store elements of the same type. Let’s explore how to access array elements in simple steps.

1. Creating an Array

Before accessing elements, let’s first create an array using the array module:

import array  

# Creating an array of integers
numbers = array.array('i', [10, 20, 30, 40, 50])  

print(numbers)  # Output: array('i', [10, 20, 30, 40, 50])

2. Accessing Elements by Index

Each element in an array is stored at a unique index starting from 0.

Index	0	1	2	3	4
Value	10	20	30	40	50

To access an element, specify its index inside square brackets []:

print(numbers[0])  # Output: 10
print(numbers[2])  # Output: 30
print(numbers[4])  # Output: 50

Important Points:

• The first element is at index 0.
• The last element is at index length – 1.
• Trying to access an index that doesn’t exist will cause an IndexError.

3. Using Negative Indexing

Python allows negative indexing, where -1 refers to the last element, -2 to the second last, and so on.

print(numbers[-1])  # Output: 50 (Last element)
print(numbers[-3])  # Output: 30 (Third element from the end)

Negative Index	-5	-4	-3	-2	-1
Value	10	20	30	40	50

Negative indexing helps when working with the last elements of an array.

4. Accessing Elements Using a Loop

You can use a loop to access multiple elements easily.

a) Using a for loop

for num in numbers:
    print(num)

Output:

10  
20  
30  
40  
50  

b) Using a while loop

i = 0
while i < len(numbers):
    print(numbers[i])
    i += 1

5. Finding the Length of an Array

Use the len() function to find the total number of elements in an array.

print(len(numbers))  # Output: 5

Python Array Methods

Introduction

Arrays in Python are used to store multiple values of the same data type. The array module provides various built-in methods to manipulate arrays, such as adding, removing, searching, and modifying elements. These methods make working with arrays easier and more efficient.

Creating an Array in Python

Before using array methods, the array module must be imported to create an array.

import array  

numbers = array.array('i', [10, 20, 30, 40, 50])  

print(numbers)  

Append Method

The append method adds a new element to the end of the array.

numbers.append(60)  
print(numbers)  

Insert Method

The insert method allows adding an element at a specific position.

numbers.insert(2, 25)  
print(numbers)  

Remove Method

This method removes the first occurrence of a specified value in the array.

numbers.remove(30)  
print(numbers)  

Pop Method

The pop method removes and returns an element from a specified index. If no index is given, it removes the last element.

removed_value = numbers.pop(3)  
print(numbers)  
print(removed_value)  

Index Method

This method returns the position of the first occurrence of a given value in the array.

position = numbers.index(50)
print(position)  

Reverse Method

The reverse method changes the order of elements in an array.

numbers.reverse()  
print(numbers)  

Count Method

The count method returns the number of times a value appears in an array.

count_10 = numbers.count(10)  
print(count_10)  

Extend Method

The extend method adds multiple values from another array or list to the existing array.

extra_numbers = array.array('i', [70, 80, 90])  
numbers.extend(extra_numbers)  
print(numbers)  

Buffer Info Method

This method provides the memory address and the number of elements in an array.

print(numbers.buffer_info())  

To List Method

This method converts an array into a Python list.

num_list = numbers.tolist()
print(num_list)  

How can elements be added to an array in Python

The append method adds an element to the end, while the insert method adds it at a specific position.

numbers.append(100)  
numbers.insert(2, 55)  

What is the difference between remove and pop methods

The remove method deletes a specific value, while the pop method removes an element at a given index and returns it.

numbers.remove(30)  
popped_element = numbers.pop(2)  

How to reverse an array in Python

The reverse method is used to reverse the elements in an array.

numbers.reverse()
print(numbers)  

How to find the index of an element in an array

The index method helps in finding the position of the first occurrence of a value in the array.

pos = numbers.index(50)
print(pos)  

2025 Python Arrays – FAQs

Summary

Python arrays offer a way to store and manipulate multiple elements of the same type efficiently. The array module provides built-in methods like append(), insert(), remove(), pop(), reverse(), and count(), among others, to work with arrays. These methods allow for easy modification and retrieval of data. Unlike lists, arrays in Python require all elements to be of the same type, making them ideal for numerical operations.

Introduction to Python Functions, Methods, and Modules