In today’s world Python holds value in the development world. Python is a high-level, interpreted programming language used for a variety of purposes, such as web development, data analysis, machine learning, and artificial intelligence.

One of the fundamental data structures in Python is the list. A list in Python is a collection of items, and you can add, remove, and modify items in a list.

In this blog, we will cover everything about append list Python, along with its definition and usage, syntax, and various ways of listing append Python. So, let’s get started without any further delays!

So, let’s get started without any further delay.

Table Of Contents show

Definition and Usage of Python Append to List:

The Python list append is a built-in Python function that adds an item to the end of a list. Python add to list modifies the original list and returns None. 

Additionally, the append list Python method can be used to add any object to a list, such as numbers, strings, or other lists.  

Syntax of List append(): 

The syntax of the list append Python is as follows: 

list.append(item)

Here, the list is the list object, and the item is the object to be added to the end of the list.

append() Parameters:

The append() method in Python only takes a single argument, which is the object you want to add to the end of the list. 

The object can be of any data type, including numbers, strings, booleans, or other lists. 

Here’s an example of append Python parameters 

my_list = [1, 2, 3]

my_list.append(‘four’)

print(my_list)

Return Value from append():

The append() method in Python does not return anything. When you call append() on a list, it simply adds the object you specify to the end of the list. It doesn’t return a new list or modify the original list in any way. 

Here’s the example of append Python return value: 

my_list = [1, 2, 3]

result = my_list.append(4)

print(result) # None

print(my_list) # [1, 2, 3, 4]

In this example, we use append() to add the number 4 to the end of the my_list list. We then assign the result of append() to a variable called result and print it out. 

Since append() doesn’t return anything, the result is None. We then print out the modified my_list, which now contains the numbers 1, 2, 3, and 4.

Add an item to a list: append():

python append to list

Source: medium.com

To add an item to a list using append(), call the method on the list object and pass the item to be added as the parameter. 

Here’s an example:

fruits = [‘apple’, ‘banana’, ‘cherry’]

fruits.append(‘orange’)

print(fruits) # Output: [‘apple’, ‘banana’, ‘cherry’, ‘orange’]

This code adds the string ‘orange’ to the end of the list of fruit.

.append() Adds a Single Item:

The append() method adds only one item to a list. You can use a loop or another method to add multiple items to a list.

If you are wondering how to use the loop in .append method, here’s an example: 

my_list = []

for i in range(5):

my_list.append(i)

print(my_list) # [0, 1, 2, 3, 4]

In this example, we created an empty list called my_list and then used a for loop to append the numbers 0 through 4 to the list. Printing out my_list now contains the numbers 0, 1, 2, 3, and 4.

.append() Returns None:

The append() method modifies the original list and returns None. Therefore, Python add to list cannot assign a new list.

For example, the following code is incorrect:

fruits = [‘apple’, ‘banana’, ‘cherry’]

new_fruits = fruits.append(‘orange’)

print(new_fruits) #Output: None  

Adding Numbers to a List with Append:

Other than the methods mentioned above, here are some more solutions about how to append to a list in Python.

Here is the example of adding a number to Python append to list:

numbers = [1, 2, 3] 

numbers.append(4)   

print(numbers)

#Output: [1, 2, 3, 4]

This code adds the integer 4 to the end of the numbers list.

Populating a List From Scratch

When working with Python, creating lists and filling them with data is often necessary. One way to do this is by using the .append() method, but another approach is to populate a list from scratch.

There are multiple ways to populate a list from scratch, but one of the most straightforward is to use a loop. This approach is especially useful when you need to create a list with a large number of items.

Here’s an example of how to append to a list in Python using a loop to populate a list from scratch: 

my_list = [] 

for i in range(10):

my_list.append(i)

print(my_list)

In this example, we start with an empty list (my_list = []) and then use a for loop to add ten items. We use the .append() method inside the loop to add each item to the list.

Once the loop is finished, we print the contents of my_list to confirm that it contains the items we added.

You can use this same approach to create lists of any size and with any type of data. 

For example, you might create a list of strings like this:

my_list = []

for i in range(5):

my_list.append(“Item ” + str(i))

print(my_list)

In this example, we’re using a loop to create a list of strings, where each string consists of the word “Item” followed by a number. The str() function converts the number to a string before it’s concatenated with the word “Item”.

This approach of populating a list from scratch can be used to create lists of any type of data, including numbers, strings, and other lists. And because you’re building the list from scratch, you have complete control over its contents and structure.

Using .append():

my_list = []

my_list.append(‘item 1’)

my_list.append(‘item 2’)

my_list.append(‘item 3’)

print(my_list) #Output: [‘item 1’, ‘item 2’, ‘item 3’]

Using a List Comprehension:

Another way to create Python append to list from scratch is using a list comprehension. Here’s how you can do it: 

squares = [i**2 for i in range(1, 11)]

print(squares) # Output: [1, 4, 9, 16, 25, 36, 49, 64, 81, 100]

Switching Back to .append()

python append to list

Source: entrepreneur.com

Switching back to .append is another simple and versatile way to populate a list from scratch in Python. Moreover, this method lets you find items on a list at any time, not just during initialization. 

Switching back to .append() is the best option when adding individual items to a list at different points in your code. For example, let’s say you have a program that reads data from a file and needs to add each line of the file to a list. You might start by initializing an empty list and then using a loop to add each line to the list, like this:

my_list = []

with open(“my_file.txt”) as file:

for line in file:

my_list.append(line.strip())

print(my_list)

In this example, we’re using the .strip() method to remove trailing whitespace from each file line before adding it to the list.

But what if you later need to add an item to the list that isn’t from the file? You may need to add a timestamp, user input, or some other kind of data. In this case, you can use the .append() method again to add the item to the end of the list:

my_list.append(“New item”)

It will add the “New item” string to the end of my_list without affecting any other items.

Using .append() in this way allows you to build up a list gradually, adding items as needed. It’s a flexible approach that can be adapted to various situations, allowing you to modify the list as your program runs easily.

Creating Stacks and Queues With Python’s .append()

You can also create stacks and queues with Python list append. In the following sections, we have mentioned codes for both. 

Implementing a Stack

Here is an example of implementing a stack using the append() method.

stack = []

stack.append(1)

stack.append(2)

stack.append(3)

print(stack) # Output: [1, 2, 3]

stack.pop() # Output: 3

Implementing a Queue

Here is an example of implementing a queue using the append() method.

queue = []

queue.append(1)

queue.append(2)

queue.append(3)

print(queue) # Output: [1, 2, 3]

queue.pop(0) # Output: 1 

Also Read: Learn How Python Remove from List Works: 7 Easy Ways

Using .append() in Other Data Structures

The .append() method is not limited to lists only. It can also add items to other data structures, such as arrays and deques.

array.append()

The array module in Python provides a way to create arrays that store values of the same type. It is more efficient than using lists when dealing with large amounts of data. You can use the .append() method to add an item to an array.

Here is an example of the .append() method: 

import array

numbers = array.array(‘i’, [1, 2, 3, 4])

numbers.append(5)

print(numbers)

Output:

array(‘i’, [1, 2, 3, 4, 5])

In the example above, we imported the array module and created an integer array named numbers with the values [1, 2, 3, 4]. We then used the .append() method to add the integer 5 to the end of the array. The output shows that the item was successfully added to the array.

deque.append() and deque.appendleft()

A deque (double-ended queue) is a data structure that allows you to add and remove items from both ends. It is implemented in Python using the deque class from the collections module. You can use the .append() method to add an item to the right end of a deque and the .appendleft() method to add an item to the left end.

Here is an example of deque.append() and deque.appendleft() for Python append to list: 

from collections import deque

numbers = deque([1, 2, 3, 4])

numbers.append(5)

numbers.appendleft(0)

print(numbers) 

Output:

deque([0, 1, 2, 3, 4, 5])

In the example above, we imported the deque class from the collections module and created a deque named numbers with the values [1, 2, 3, 4]. 

We then used the .append() method to add the integer 5 to the right end of the deque and the .appendleft() method to add the integer 0 to the left end. The output shows that the items were successfully added to the deque. 

Conclusion 

In this article, we learned about Python’s .append() method, its syntax, parameters, and return value. We also explored how to use .append() to add items to a list and how to populate a list using .append() and list comprehensions. Additionally, we looked at how .append() can be used to create stacks and queues and how it can be used with other data structures such as arrays and deques. The .append() method is a useful tool in Python programming, and understanding how it works will allow you to write more efficient and effective code.

More from The Techconcord

For more valuable information and tips, keep visiting Techconcord.