diff --git a/pandas/core/frame.py b/pandas/core/frame.py index d2da52ba7bdd0..e14325759e509 100644 --- a/pandas/core/frame.py +++ b/pandas/core/frame.py @@ -4740,6 +4740,73 @@ def duplicated( Returns ------- Series + Boolean series for each duplicated rows. + + See Also + -------- + Index.duplicated : Equivalent method on index. + Series.duplicated : Equivalent method on Series. + Series.drop_duplicates : Remove duplicate values from Series. + DataFrame.drop_duplicates : Remove duplicate values from DataFrame. + + Examples + -------- + Consider dataset containing ramen rating. + + >>> df = pd.DataFrame({ + ... 'brand': ['Yum Yum', 'Yum Yum', 'Indomie', 'Indomie', 'Indomie'], + ... 'style': ['cup', 'cup', 'cup', 'pack', 'pack'], + ... 'rating': [4, 4, 3.5, 15, 5] + ... }) + >>> df + brand style rating + 0 Yum Yum cup 4.0 + 1 Yum Yum cup 4.0 + 2 Indomie cup 3.5 + 3 Indomie pack 15.0 + 4 Indomie pack 5.0 + + By default, for each set of duplicated values, the first occurrence + is set on False and all others on True. + + >>> df.duplicated() + 0 False + 1 True + 2 False + 3 False + 4 False + dtype: bool + + By using 'last', the last occurrence of each set of duplicated values + is set on False and all others on True. + + >>> df.duplicated(keep='last') + 0 True + 1 False + 2 False + 3 False + 4 False + dtype: bool + + By setting ``keep`` on False, all duplicates are True. + + >>> df.duplicated(keep=False) + 0 True + 1 True + 2 False + 3 False + 4 False + dtype: bool + + To find duplicates on specific column(s), use ``subset``. + + >>> df.duplicated(subset=['brand']) + 0 False + 1 True + 2 False + 3 True + 4 True + dtype: bool """ from pandas.core.sorting import get_group_index from pandas._libs.hashtable import duplicated_int64, _SIZE_HINT_LIMIT