Skip to content

Add is_palindrome_ignore_case_and_spaces to strings/palindrome.py #14907

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
kaviya-ns wants to merge 3 commits into
base: master
Choose a base branch
from
+33 −0
Open

Add is_palindrome_ignore_case_and_spaces to strings/palindrome.py #14907

Changes from all commits
Commits
Show all changes
3 commits
Select commit Hold shift + click to select a range
01db263
Add is_palindrome_ignore_case_and_spaces to strings/palindrome.py
kaviya-ns Jul 7, 2026
2aa4f26
Address review: handle punctuation, add dedicated test data for new f…
kaviya-ns Jul 9, 2026
396a479
Revert unrelated benchmark timing comments per review
kaviya-ns Jul 11, 2026
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
33 changes: 33 additions & 0 deletions strings/palindrome.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -81,6 +81,35 @@ def is_palindrome_slice(s: str) -> bool:
return s == s[::-1]


def is_palindrome_ignore_case_and_spaces(s: str) -> bool:

@zain-cs zain-cs Jul 11, 2026

Copy link
Copy Markdown
Contributor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Nice implementation and the docstring covers it well. Small naming nit: since .isalnum() also strips punctuation, not just case and spaces, might be worth reflecting that in the function name too (or it's fine as-is if the broader scope was intentional).

@kaviya-ns kaviya-ns Jul 11, 2026

Copy link
Copy Markdown
Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

The broader scope (also stripping punctuation) was intentional. Since a fully descriptive name would get pretty long, I added a note in the docstring clarifying it also ignores punctuation, so the behavior is explicit there. Let me know if you'd still like me to rename it and I can update it.

"""
Return True if s is a palindrome, ignoring case, spaces, and punctuation.
Otherwise return False.

>>> is_palindrome_ignore_case_and_spaces("A man a plan a canal Panama")
True
>>> is_palindrome_ignore_case_and_spaces("Was it a car or a cat I saw?")
True
>>> is_palindrome_ignore_case_and_spaces("Hello World")
False
>>> is_palindrome_ignore_case_and_spaces("Never Odd or Even")
True
>>> is_palindrome_ignore_case_and_spaces("")
True
"""
s = "".join(char.lower() for char in s if char.isalnum())
return s == s[::-1]


test_data_ignore_case_and_spaces = {
"A man a plan a canal Panama": True,
"Was it a car or a cat I saw?": True,
"Hello World": False,
"Never Odd or Even": True,
"": True,
}


def benchmark_function(name: str) -> None:
stmt = f"all({name}(key) == value for key, value in test_data.items())"
setup = f"from __main__ import test_data, {name}"
Expand All @@ -94,6 +123,8 @@ def benchmark_function(name: str) -> None:
assert is_palindrome(key) == is_palindrome_recursive(key)
assert is_palindrome(key) == is_palindrome_slice(key)
print(f"{key:21} {value}")
for key, value in test_data_ignore_case_and_spaces.items():
assert is_palindrome_ignore_case_and_spaces(key) == value
print("a man a plan a canal panama")

# finished 500,000 runs in 0.46793 seconds

@zain-cs zain-cs Jul 11, 2026

Copy link
Copy Markdown
Contributor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

These benchmark timing changes for is_palindrome, is_palindrome_slice, and is_palindrome_recursive look unrelated to this PR's actual purpose — was this from a re-run on a different machine? Might be worth reverting these lines to keep the diff focused just on the new function.

@kaviya-ns kaviya-ns Jul 11, 2026

Copy link
Copy Markdown
Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

thanks! . those were leftover from a local re-run on my machine. I've reverted them back to the original values.

Expand All @@ -104,3 +135,5 @@ def benchmark_function(name: str) -> None:
benchmark_function("is_palindrome_recursive")
# finished 500,000 runs in 2.08679 seconds
benchmark_function("is_palindrome_traversal")
# finished 500,000 runs in 4.27493 seconds
benchmark_function("is_palindrome_ignore_case_and_spaces")