query函数
index=df.query('index>200').index (引号为必须）
loc, iloc函数
df.loc[(df['group']=='treatment')!=(df['landing_page']=='new')].count()
df_test=df.loc[~((df['group']=='treatment')!=(df['landing_page']=='new'))]
df_test1.loc[(df_test1.['group']=='treatment')].['converted'].mean()
duplicated, drop_duplicates函数
df_test.loc(df_test['user_id'].duplicated(keep=False))
df_test1=df_test.drop_duplicates('user_id',keep='first')
