python - Pandas 将时间列添加到日期索引

Question

我有一个数据框，日期索引类型是时间戳，时间列是datetime.Time:

            Time  Value
Date
2004-05-01  0:15  3.58507  
2004-05-02  0:30  3.84625
              ...

如何将其转换为:

                    Value
Date
2004-05-01 0:15     3.74618
2004-05-01 0:30     3.58507
2004-05-01 0:45     3.30998

我写了一个可以工作的代码，但它不是很 pythonic:

ind = frame.index.get_level_values(0).tolist()
tms = frame['Time']
new_ind = []
for i in range(0, len(ind)):
    tm = tms[i]
    val = ind[i] + timedelta(hours=tm.hour, minutes=tm.minute, seconds=tm.second)
    new_ind.append(val)

frame.index = new_ind
del frame['Time']

Answer 1

您可以先转换列 Time to_timedelta , 然后添加到 index, drop列 Time 并在必要时设置索引 name:

df.Time = pd.to_timedelta(df.Time + ':00', unit='h')
df.index = df.index + df.Time
df = df.drop('Time', axis=1)
df.index.name = 'Date'
print (df)
                       Value
Date                        
2004-05-01 00:15:00  3.58507
2004-05-02 00:30:00  3.84625

如果 Time 列对我来说是 datetime.time 首先转换为 string(如有必要，添加 :00):

df.Time = pd.to_timedelta(df.Time.astype(str), unit='h')
df.index = df.index + df.Time
df = df.drop('Time', axis=1)
df.index.name = 'Date'
print (df)
                       Value
Date                        
2004-05-01 00:15:00  3.58507
2004-05-02 00:30:00  3.84625