Pandas提供了duplicated、Index.duplicated、drop_duplicates函數(shù)來標記及刪除重復(fù)記錄

duplicated函數(shù)用于標記Series中的值、DataFrame中的記錄行是否是重復(fù)，重復(fù)為True，不重復(fù)為False

pandas.DataFrame.duplicated(self, subset=None, keep='first')

pandas.Series.duplicated(self, keep='first')

其中參數(shù)解釋如下：

subset：用于識別重復(fù)的列標簽或列標簽序列，默認所有列標簽

keep=‘frist'：除了第一次出現(xiàn)外，其余相同的被標記為重復(fù)

keep='last'：除了最后一次出現(xiàn)外，其余相同的被標記為重復(fù)

keep=False：所有相同的都被標記為重復(fù)

import numpy as npimport pandas as pd #標記DataFrame重復(fù)例子df = pd.DataFrame({'col1': ['one', 'one', 'two', 'two', 'two', 'three', 'four'], 'col2': [1, 2, 1, 2, 1, 1, 1],   'col3':['AA','BB','CC','DD','EE','FF','GG']},index=['a', 'a', 'b', 'c', 'b', 'a','c'])#duplicated(self, subset=None, keep='first')#根據(jù)列名標記#keep='first'df.duplicated()#默認所有列，無重復(fù)記錄df.duplicated('col1')#第二、四、五行被標記為重復(fù)df.duplicated(['col1','col2'])#第五行被標記為重復(fù)#keep='last'df.duplicated('col1','last')#第一、三、四行被標記重復(fù)df.duplicated(['col1','col2'],keep='last')#第三行被標記為重復(fù)#keep=Falsedf.duplicated('col1',False)#Series([True,True,True,True,True,False,False],index=['a','a','b','c','b','a','c'])df.duplicated(['col1','col2'],keep=False)#在col1和col2列上出現(xiàn)相同的，都被標記為重復(fù)type(df.duplicated(['col1','col2'],keep=False))#pandas.core.series.Series#根據(jù)索引標記df.index.duplicated()#默認keep='first',第二、五、七行被標記為重復(fù)df.index.duplicated(keep='last')#第一、二、三、四被標記為重復(fù)df[df.index.duplicated()]#獲取重復(fù)記錄行df[~df.index.duplicated('last')]#獲取不重復(fù)記錄行#標記Series重復(fù)例子#duplicated(self, keep='first')s = pd.Series(['one', 'one', 'two', 'two', 'two', 'three', 'four'] ,index= ['a', 'a', 'b', 'c', 'b', 'a','c'],name='sname')s.duplicated()s.duplicated('last')s.duplicated(False)#根據(jù)索引標記s.index.duplicated()s.index.duplicated('last')s.index.duplicated(False)

drop_duplicates函數(shù)用于刪除Series、DataFrame中重復(fù)記錄，并返回刪除重復(fù)后的結(jié)果

pandas.DataFrame.drop_duplicates(self, subset=None, keep='first', inplace=False)

pandas.Series.drop_duplicates(self, keep='first', inplace=False)

#刪除DataFrame重復(fù)記錄例子 #drop_duplicates(self, subset=None, keep='first', inplace=False) df.drop_duplicates() df.drop_duplicates('col1')#刪除了df.duplicated('col1')標記的重復(fù)記錄 df.drop_duplicates('col1','last')#刪除了df.duplicated('col1','last')標記的重復(fù)記錄 df1.drop_duplicates(['col1','col2'])#刪除了df.duplicated(['col1','col2'])標記的重復(fù)記錄 df.drop_duplicates('col1',keep='last',inplace=True)#inplace=True表示在原DataFrame上執(zhí)行刪除操作 df.drop_duplicates('col1',keep='last',inplace=False)#inplace=False返回一個副本 #刪除Series重復(fù)記錄例子 #drop_duplicates(self, keep='first', inplace=False) s.drop_duplicates()