Python string swapcase() Method

swapcase() method in Python is used to return a new string where all the uppercase characters in the original string are converted to lowercase, and all the lowercase characters are converted to uppercase.

Let's us understand this with the help of an example:

s = "I love Python"

swapped_text = s.swapcase()
print(swapped_text)  

i LOVE pYTHON

Explanation:

• The uppercase characters are converted to lowercase.
• The lowercase characters are converted to uppercase.
• The result is a toggle-case version of the original string.

Syntax of String swapcase() method

string.swapcase()

Parameters

• The swapcase() method does not take any parameters.

Return Type

• Returns a new string where all uppercase characters are converted to lowercase and all lowercase characters are converted to uppercase.

Simple toggle case

Let’s see how sswapcase() works with a mixed-case string:

s = "Python IS Awesome!"

res = s.swapcase()
print(res)  

pYTHON is aWESOME!

Explanation:

• Uppercase characters P, I, S, and A are converted to lowercase.
• Lowercase characters y, t, h, o, n, and w are converted to uppercase.
• The method returns a toggle-case version of the input string.

Handling numeric and special characters

The swapcase()method does not affect numeric or special characters:

s = "123 Python!"

res = s.swapcase()
print(res)  

123 pYTHON!

Explanation:

• The numbers 123 and the special character ! remain unchanged.
• Only alphabetic characters are toggled.

Applying swapcase() to an all-uppercase string

What happens if the string contains only uppercase characters?

s = "HELLO"
res = s.swapcase()
print(res)  

hello

Explanation:

• All uppercase characters are converted to lowercase.
• The method works seamlessly with strings of any case.

4. Applying swapcase() to an all-lowercase string

Similarly, let’s see the result with an all-lowercase string:

s = "world"
res = s.swapcase()
print(res) 

WORLD

Explanation:

• All lowercase characters are converted to uppercase.
• The method ensures a complete toggle of the string’s case.