將數據框分組並根據條件在其中選擇一個單元格

Question

我的數據集看起來像這樣Tr, Date, Time AV81312,20161014,121000 AV81312,20161014,160221 AV85012,20170422,150858 AV85012,20161108,11137 AV86157,20170426,45747 AV86157,20170426,45744 AV86157,20160813,134312

我只需要從每個具有最新記錄的Tr中選擇一個項目，即具有更高日期和時間的最新記錄

所需的輸出是Tr, Date, Time AV81312,20161014,160221 AV85012,20170422,150858 AV86157,20170426,45747

我的代碼是

df2 = read_csv("sample.csv") df2 = df2.values x = [] for i in df2: for j in df2: if i[2] == j[2]: if i[3] >= j[3]: x.append(i)它沒有按預期工作

Answer 1

用 -

df['Date_Time'] = pd.to_datetime(df['Date'].astype(str).str.cat(df['Time'].astype(str)),format='%Y%m%d%H%M%S')
df.loc[df.groupby('Tr')['Date_Time'].idxmax()].drop('Date_Time', axis=1)

輸出

        Tr      Date    Time
0  AV81312  20161014  160221
1  AV85012  20170422  150858
2  AV86157  20170426   45747