Python: Swap cases of a given string

Last update on April 19 2025 13:05:04 (UTC/GMT +8 hours)

Swap cases in string.

Write a Python program to swap cases in a given string.

Sample Solution:

Python Code:

# Define a function to swap the case of characters in a string
def swap_case_string(str1):
    # Initialize an empty string to store the result
    result_str = ""
    
    # Iterate through each character in the input string
    for item in str1:
        # Check if the character is uppercase
        if item.isupper():
            # If uppercase, convert to lowercase and append to the result string
            result_str += item.lower()
        else:
            # If lowercase, convert to uppercase and append to the result string
            result_str += item.upper()
    
    # Return the final swapped case string
    return result_str

# Test the function with different input strings and print the results
print(swap_case_string("Python Exercises"))
print(swap_case_string("Java"))
print(swap_case_string("NumPy"))

Sample Output:

pYTHON eXERCISES
jAVA
nUMpY

Flowchart:

For more Practice: Solve these Related Problems:

Write a Python program to swap the case of each letter in a string using the swapcase() method.
Write a Python program to implement case swapping manually by iterating over each character and toggling its case.
Write a Python program to use a list comprehension to produce a new string where uppercase letters become lowercase and vice versa.
Write a Python program to combine slicing and conditional logic to swap cases in a given string without built-in methods.

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