Skip to content

BUG: Duplicated returns boolean dataframe #25234

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

Merged
merged 2 commits into from
Feb 11, 2019
Merged

BUG: Duplicated returns boolean dataframe #25234

Show file tree
Hide file tree
Changes from 1 commit
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
2a264e8
BUG: Duplicated returns boolean dataframe
Feb 9, 2019
97307dd
Resolved issues brought up in code review
Feb 9, 2019
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
2 changes: 2 additions & 0 deletions doc/source/whatsnew/v0.25.0.rst
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -68,6 +68,8 @@ Performance Improvements
Bug Fixes
~~~~~~~~~

- Bug in using duplicated with empty dataframes (:issue:`25184`)
Copy link
Contributor

Choose a reason for hiding this comment

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

say more like

:meth:DataFrame.duplicate() on empty dataframe was not return a boolean dtyped Series

Copy link
Contributor

Choose a reason for hiding this comment

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

this can go in 0.24.2


Categorical
^^^^^^^^^^^

Expand Down
2 changes: 1 addition & 1 deletion pandas/core/frame.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -4636,7 +4636,7 @@ def duplicated(self, subset=None, keep='first'):
from pandas._libs.hashtable import duplicated_int64, _SIZE_HINT_LIMIT

if self.empty:
return Series()
return Series(dtype=bool)

def f(vals):
labels, shape = algorithms.factorize(
Expand Down
6 changes: 6 additions & 0 deletions pandas/tests/frame/test_duplicates.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -182,6 +182,12 @@ def test_drop_duplicates():
assert df.duplicated(keep=keep).sum() == 0


def test_duplicated_on_empty_frame_gives_back_frame():
Copy link
Contributor

Choose a reason for hiding this comment

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

can you add the issue number as a comment here, rename the test to

test_duplicated_on_empty_frame

df = DataFrame(columns=['a', 'b'])
dupes = df.duplicated('a')
Copy link
Contributor

Choose a reason for hiding this comment

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

result =
expected =
tm.assert_frame_equal(result, expected)

tm.assert_frame_equal(df[dupes], df)


def test_drop_duplicates_with_duplicate_column_names():
# GH17836
df = DataFrame([
Expand Down