Python List | What Are Lists In Python ?
(Best 5 minute Revision)
A python list is an ordered collection that supports indexing. It allows duplicate elements and it’s mutable in nature that means it allows modification . Python List is a versatile data structure that can contain multiple types of data. Yes! You read it right, List allows you to store different types of data elements like integer, float, bool, and even other lists inside it. We have discussed the nested list part later but let’s focus on basics first.
List is always created in two ways:
1. a = [5, 7, 9, 11, 13] # using []
2. b = list (5, 7, 9, 11, 13) #using list()
How Python List works?
1.Indexing
List supports both positive and negative indexing as you can see in the above image. Here, the positive indexing starts from indexing first element as ‘0’ and negative indexing starts from indexing last element as ‘-1’.
So, when we print the above list we get output as [5, 7, 9, 11, 13]. But, when we want to print a particular element present at a particular index, then we can pass the index to print, like print(a[0]) and you will get element present at index 0 printed.
2.Slicing
We use slicing (:) operator to access sublist or multiple elements at a time from a single list.
Syntax: [start: stop: step]
- start – it’s default value remains ‘0’, if not passed by user.
- stop – basically it refers to the length till which the slicing is to be done, it’s default value remains ‘len(list)’.
- step – it is the number of increment we need to do, i.e., either we need to increment slicing by 1 step or 2 step. On default it’s set to ‘+1’.
For example, list = [5, 7, 9, 11, 13] (you may refer to their indexing in the picture above)
list2 = list[1:4] —-> output : [7, 9, 11]
list3 = list[1:5:2] —-> output: [7, 11]
list 4 = list[::2] —-> output : [5, 9, 13]
3.Arrays using List
In python, arrays can be both homogeneous and heterogeneous. The heterogeneous arrays are implemented in 2 ways, that are, using NumPy module or by using lists.
Using python list collection, we can make array accept heterogeneous data also. Though, it has a contiguous memory but list collection is way more efficient in memory management, however, it’s still slower than NumPy module.
4.Methods in List
List has different methods to make your work easy and smart:
- Create list: list()
- Add elements: append(), insert(), extend
- Remove element: pop(), remove(),clear(), del keyword
- modify/change elements: indexing, slicing
5.Nested Lists
A nested list in Python is simply a list that contains other lists as its elements. This structure is useful for creating multi-dimensional data, like tables, grids, or matrices where each inner list might represent a row, category, or group of values.
Since you’re working with lists inside lists, accessing elements requires multiple levels of indexing. You use one index to access the outer list and another to access the specific item inside the inner list.
matrix = [
[1, 2, 3],
[4, 5, 6],
[7, 8, 9]
]
print(matrix[1][2]) # Output: 6In the above code:
matrix[1]accesses the second list:[4, 5, 6]matrix[1][2]accesses the third element in that list:6
This concept is key when working with structured data in Python, especially in areas like data science, image processing, or game development.
FAQs About Python List
Q1. What is a Python List?
A Python List is a mutable, ordered collection that can store elements of different data types, including other lists.
Q2. How is a list different from a tuple in Python?
The main difference is that a list is mutable (can be changed), whereas a tuple is immutable (cannot be changed).
Q3. Can a Python List contain duplicate values?
Yes, Python Lists can store duplicate elements.
Q4. How do I add or remove elements from a Python List?
You can use methods like append(), insert(), and extend() to add, and remove() or pop() to delete elements from a list.
Q5. Can I store different data types in a Python List?
Yes, Python Lists can hold mixed data types, such as integers, strings, floats, and even other lists.
Q6. What are some common operations on Python Lists?
Common operations include slicing, iteration, sorting, concatenation, and list comprehensions.
Q7. Are Python Lists zero-indexed?
Yes, Python Lists start indexing from 0, meaning the first element is accessed using list[0].
Q8. How do I copy a list in Python without affecting the original?
Use list.copy() or slicing (list[:]) to create a shallow copy of a list.
Conclusion
Understanding Python List is one of the most essential skills for any programmer — especially if you’re just starting out. Lists allow you to store and organize data efficiently, and they form the backbone of many real-world Python applications.
Whether you’re working on simple programs or diving into data science, mastering lists will make your coding journey smoother and more productive.
💡 Remember:
Lists are flexible, dynamic, and easy to use.
You can store numbers, strings, even other lists!
With just a few lines of code, you can manipulate large sets of data.
If you’re serious about learning Python, make sure to visit and explore our Python for beginners article — it includes exercises, examples, and a complete roadmap to mastering Python, step by step.