Python: Reverse the case of all strings. For those strings, which contain no letters, reverse the strings

Last update on March 22 2025 13:48:31 (UTC/GMT +8 hours)

Reverse Case or Reverse Strings

Write a Python program to reverse the case of all strings. For those strings, which contain no letters, reverse the strings.

Input:
['cat', 'catatatatctsa', 'abcdefhijklmnop', '124259239185125', '', 'foo', 'unique']
Output:
['CAT', 'CATATATATCTSA', 'ABCDEFHIJKLMNOP', '521581932952421', '', 'FOO', 'UNIQUE']

Input:
['Green', 'Red', 'Orange', 'Yellow', '', 'White']
Output:
['gREEN', 'rED', 'oRANGE', 'yELLOW', '', 'wHITE']

Input:
['Hello', '!@#', '!@#$', '123#@!']
Output:
['hELLO', '!@#', '!@#$', '123#@!']

Visual Presentation:

Sample Solution:

Python Code:

# Define a function named 'test' that takes a list of strings as input and returns a modified list
def test(strs: list[str]) -> list[str]:
    # Use a list comprehension to create a new list with modified strings
    # If a string contains any alphabetic characters, reverse its case; otherwise, reverse the string
    return [s.swapcase() if any(c.isalpha() for c in s) else s[::-1] for s in strs]

# Create a list of strings named 'strs'
strs = ['cat', 'catatatatctsa', 'abcdefhijklmnop', '124259239185125', '', 'foo', 'unique']
# Print a message indicating the task and the original list
print("Original list:")
# Print the original list of strings
print(strs)
# Print a message indicating the task and the result of the test function applied to 'strs'
print("Reverse the case of all strings. For those strings which contain no letters, reverse the strings:")
# Print the result of the test function applied to 'strs'
print(test(strs))

# Create another list of strings named 'strs'
strs = ['Green', 'Red', 'Orange', 'Yellow', '', 'White']
# Print a message indicating the task and the original list
print("\nOriginal list:")
# Print the original list of strings
print(strs)
# Print a message indicating the task and the result of the test function applied to 'strs'
print("Reverse the case of all strings. For those strings which contain no letters, reverse the strings:")
# Print the result of the test function applied to 'strs'
print(test(strs))

# Create yet another list of strings named 'strs'
strs = ["Hello", "!@#", "!@#$", "123#@!"]
# Print a message indicating the task and the original list
print("\nOriginal list:")
# Print the original list of strings
print(strs)
# Print a message indicating the task and the result of the test function applied to 'strs'
print("Reverse the case of all strings. For those strings which contain no letters, reverse the strings:")
# Print the result of the test function applied to 'strs'
print(test(strs))

Sample Output:

Original list:
['cat', 'catatatatctsa', 'abcdefhijklmnop', '124259239185125', '', 'foo', 'unique']
Reverse the case of all strings. For those strings which contain no letters, reverse the strings:
['CAT', 'CATATATATCTSA', 'ABCDEFHIJKLMNOP', '521581932952421', '', 'FOO', 'UNIQUE']

Original list:
['Green', 'Red', 'Orange', 'Yellow', '', 'White']
Reverse the case of all strings. For those strings which contain no letters, reverse the strings:
['gREEN', 'rED', 'oRANGE', 'yELLOW', '', 'wHITE']

Original list:
['Hello', '!@#', '!@#$', '123#@!']
Reverse the case of all strings. For those strings which contain no letters, reverse the strings:
['hELLO', '#@!', '$#@!', '!@#321']

Flowchart:

For more Practice: Solve these Related Problems:

• Write a Python program that toggles the case of each letter in a list of strings and reverses any string containing no alphabetic characters.
• Write a Python program to process a list of strings such that for each string containing letters, the case is reversed, and for strings with only digits or symbols, the string is reversed.
• Write a Python program to alternate between reversing the case and completely reversing the string based on the string’s length.
• Write a Python program to transform a list of strings by inverting the case for letter-containing strings and reversing others, using map() and lambda functions.

Python Code Editor :

Have another way to solve this solution? Contribute your code (and comments) through Disqus.

Previous: Find the first n Fibonacci numbers.
Next: Find the product of the units digits in the numbers.