python - 在python中转换日期时间分钟和年份

Question

我有一个数据框如下

customerid            mydate

    123              2016-08-15 18:22:40
    234              2017-08-15 42:34.04
    234              39:35.01

mydate 列是混合的，有些有年份，有些只有时间。 mydate 列是一个对象，但我想将其转换为日期时间，如下所示

df['mydate']     =  pd.to_datetime(df['mydate'], format='%Y-%m-%d %H:%M:%S')

但我收到以下错误

ValueError: time data 39:35.01 doesn't match format specified 

Answer 1

您可以使用:

#get today date
today = pd.Timestamp.today().floor('D')
#split dates by whitespace
s = df['mydate'].str.split()
#first part convert to datetime if possible replace non exist dates to today
df['date'] =  pd.to_datetime(s.str[0], errors='coerce').fillna(today)
#non exist second part of splited values replace by first part
s1 = s.str[1].combine_first(s.str[0])
#if 3. character from back is . add zero hours and convert to timedeltas
df['td']  =  pd.to_timedelta(s1.mask(s1.str[-3] == '.', '00:'+ s1))
#add timedelta to dates
df['datefinal'] = df['date'] + df['td']
print (df)
  customerid               mydate       date              td  \
0        123  2016-08-15 18:22:40 2016-08-15        18:22:40   
1        234  2017-08-15 42:34.04 2017-08-15 00:42:34.040000   
2        234             39:35.01 2018-11-21 00:39:35.010000   

                datefinal  
0 2016-08-15 18:22:40.000  
1 2017-08-15 00:42:34.040  
2 2018-11-21 00:39:35.010