Question

我有一个 df 为：

Name    Date       Time
 A   02/20/2021   12:30:06
 A   02/20/2021   12:30:20
 A   02/21/2021   12:30:20
 A   02/22/2021   02:30:30

我试图将它们组合成一个日期时间并将当前行与前一行相减以获得以秒为单位的日期时间的差异列，例如：

Name   Date        Time      diff
 A    02/20/2021   12:30:06   
 A    02/20/2021   12:30:20   14 seconds
 A    02/21/2021   12:30:20   86400 seconds
 A    02/22/2021   02:30:30   50410 seconds

我正在尝试：

df['Datetime'] = df['Date'].astype(str)+' '+df['Time'].astype(str)


df[['diff']] = df.groupby('Name')[['Datetime', 'Result']].diff()

但它给了我 0 days 00:00:10 的输出。我无法在任何地方找到合适的解决方案。提前致谢

Answer 1

首先通过 to_datetime 创建日期时间，然后通过 Series.dt.total_seconds 转换时间增量：

df['Datetime'] = pd.to_datetime(df['Date'].astype(str) +' '+df['Time'].astype(str))

df['diff'] = df.groupby('Name')['Datetime'].diff().dt.total_seconds()
print (df)
  Name        Date      Time            Datetime     diff
0    A  02/20/2021  12:30:06 2021-02-20 12:30:06      NaN
1    A  02/20/2021  12:30:20 2021-02-20 12:30:20     14.0
2    A  02/21/2021  12:30:20 2021-02-21 12:30:20  86400.0
3    A  02/22/2021  02:30:30 2021-02-22 02:30:30  50410.0

对于整数，对于缺失值的整数使用 integer na：

df['diff'] = df.groupby('Name')['Datetime'].diff().dt.total_seconds().astype('Int64')
print (df)
  Name        Date      Time            Datetime   diff
0    A  02/20/2021  12:30:06 2021-02-20 12:30:06   <NA>
1    A  02/20/2021  12:30:20 2021-02-20 12:30:20     14
2    A  02/21/2021  12:30:20 2021-02-21 12:30:20  86400
3    A  02/22/2021  02:30:30 2021-02-22 02:30:30  50410

如果需要秒 floats 添加自定义函数 Series.map：

df['Datetime'] = pd.to_datetime(df['Date'].astype(str) +' '+df['Time'].astype(str))

f = lambda x: '' if pd.isna(x) else f'{int(x)} seconds'
df['diff'] = df.groupby('Name')['Datetime'].diff().dt.total_seconds().map(f)
print (df)
  Name        Date      Time            Datetime           diff
0    A  02/20/2021  12:30:06 2021-02-20 12:30:06               
1    A  02/20/2021  12:30:20 2021-02-20 12:30:20     14 seconds
2    A  02/21/2021  12:30:20 2021-02-21 12:30:20  86400 seconds
3    A  02/22/2021  02:30:30 2021-02-22 02:30:30  50410 seconds

减去日期时间列并以秒为单位获得结果熊猫

1 个答案: