Python supports object-oriented programming and has a concise, readable, and easy-to-learn syntax. It is no wonder that it is one of the most popular programming languages. An integral part of Python are its built-in functions. You would have surely used some of these functions in your programs. 

We've written a series of articles to help you learn and brush up on the most useful Python functions. In this article, we’ll learn more about Python's lower() function and how to use it. 

If you are preparing for a tech interview, check out our technical interview checklist, interview questions page, and salary negotiation e-book to get interview-ready! Also, read Python String join() Method, Python Exit commands, and Type and Isinstance In Python for more content on Python coding interview preparation.

Having trained over 10,000 software engineers, we know what it takes to crack the most challenging tech interviews. Since 2014, Interview Kickstart alums have landed lucrative offers from FAANG and Tier-1 tech companies, with an average salary hike of 49%. The highest ever offer received by an IK alum is a whopping $1.267 Million!

At IK, you get the unique opportunity to learn from expert instructors who are hiring managers and tech leads at Google, Facebook, Apple, and other top Silicon Valley tech companies.

Want to nail your next tech interview? Sign up for our FREE Webinar.

In this article, we’ll cover:

• What Is the lower() Function in Python and What Does It Do?
• The lower() Function in Python: Syntax
• The lower() Function in Python: Example
• FAQs on the Lower Case Function lower() in Python

What Is the lower() Function in Python and What Does It Do?

Python’s lower() function converts all the uppercase characters in a string to lowercase characters and returns the modified string. 

One common application of the lower() function in Python is to check if the given two strings are the same or not. We’ll show you how to do this using an example later in the post.

Note: If you want to convert all characters in a string to uppercase, use the Python function upper(). And if you want to swap between lowercase and uppercase, use the swapcase() function in Python. 

The lower() Function in Python: Syntax

string.lower()

stringName.lower()

The lower() function in Python does not take any parameters. Python’s lower() function returns an all lowercase string made by converting all uppercase characters to lowercase from the given string. If there are no uppercase characters in the given string, the original string is returned as it is.

The lower() Function in Python: Example

Want to learn how to write a function in Python that will convert all uppercase characters to lowercase? Let’s take a look at how lower() works. You can apply the function lower() to convert all uppercase characters to lowercase in Python. What’s more? Here, we take a look at how you can apply the function lower() in Python next time you need it:

How to Use the lower() Function in Python: Code 

stringExample = "I will be converted to LowerCase @123."

print("Original string: " + stringExample)

lowercaseExample = stringExample.lower()

print("String converted to lowercase using lower(): " + lowercaseExample +"\n")

#To check if two strings are the same in meaning using lower()

stringExample1 = "I wiLl be converTed to lowerCASE @123."

stringExample2 = "I will be converted to lowerCase @345!"

print("Strings to be compared with the original string:")

print("String1: " + stringExample1)

print("String2: " + stringExample2)

print("\n")

if(stringExample.lower() == stringExample1.lower()):

    print("String 1 is the same as the original string.")

else:

    print("String 1 is not the same as the original string.")

if(stringExample.lower() == stringExample2.lower()):

    print("String 2 is the same as the original string.")

else:

    print("String 2 is not the same as the original string.")

Output

Original string: I will be converted to LowerCase @123.

String converted to lowercase using lower(): i will be converted to lowercase @123.

Strings to be compared with the original string:

String1: I wiLl be converTed to lowerCASE @123.

String2: I will be converted to lowerCase @345!

String 1 is the same as the original string.

String 2 is not the same as the original string.

Found this article helpful? You can learn about more Python functions in our learn folder. 

FAQs on the Lower Case Function lower() in Python

Q1. Does the lower case function lower() in Python take any parameters?

No, the lower() function acts on a string and does not take any parameters.

Q2. What does the lower() function in Python return?

Python’s lower() function returns the original string converted to all lowercase.

Q3. How does the lower() function in Python work?

Python’s lower() function converts any uppercase characters into lowercase and does nothing to other characters in the original string.

Q4. What are upper() and lower() functions in Python?

Both upper() and lower() functions are built-in functions for string-handling in Python. For a given string, upper() converts the string to all uppercase, while lower() converts the string to all lowercase. 

Q5. How does Python determine lowercase?

Python determines uppercase with the help of the islower() function in Python.

Ready to Nail Your Next Coding Interview?

Whether you’re a coding engineer gunning for a software developer or software engineer role, a tech lead, or you’re targeting management positions at top companies, IK offers courses specifically designed for your needs to help you with your technical interview preparation!

If you’re looking for guidance and help with getting started, sign up for our FREE webinar. As pioneers in the field of technical interview preparation, we have trained thousands of software engineers to crack the most challenging coding interviews and land jobs at their dream companies, such as Google, Facebook, Apple, Netflix, Amazon, and more!

Sign up now!