[英]How do I properly set the Datetime as an index for a Pandas dataframe?
[英]How do I properly set the Datetimeindex for a Pandas datetime object in a dataframe?
我有一個熊貓數據框:
lat lng alt days date time
0 40.003834 116.321462 211 39745.175405 2008-10-24 04:12:35
1 40.003783 116.321431 201 39745.175463 2008-10-24 04:12:40
2 40.003690 116.321429 203 39745.175521 2008-10-24 04:12:45
3 40.003589 116.321427 194 39745.175579 2008-10-24 04:12:50
4 40.003522 116.321412 190 39745.175637 2008-10-24 04:12:55
5 40.003509 116.321484 188 39745.175694 2008-10-24 04:13:00
為此,我試圖將 df['date'] 和 df['time'] 列轉換為日期時間。 我可以:
df['Datetime'] = pd.to_datetime(df['date']+df['time'])
df = df.set_index(['Datetime'])
del df['date']
del df['time']
我得到:
lat lng alt days
Datetime
2008-10-2404:12:35 40.003834 116.321462 211 39745.175405
2008-10-2404:12:40 40.003783 116.321431 201 39745.175463
2008-10-2404:12:45 40.003690 116.321429 203 39745.175521
2008-10-2404:12:50 40.003589 116.321427 194 39745.175579
2008-10-2404:12:55 40.003522 116.321412 190 39745.175637
但是如果我嘗試:
df.between_time(time(1),time(22,59,59))['lng'].std()
我收到一個錯誤 - 'TypeError: Index must be DatetimeIndex'
所以,我也試過設置 DatetimeIndex:
df['Datetime'] = pd.to_datetime(df['date']+df['time'])
#df = df.set_index(['Datetime'])
df = df.set_index(pd.DatetimeIndex(df['Datetime']))
del df['date']
del df['time']
這也會引發錯誤 - 'DateParseError: unknown string format'
如何正確創建日期時間列和 DatetimeIndex 以便 df.between_time() 正常工作?
為了簡化基魯巴哈蘭的回答:
df['Datetime'] = pd.to_datetime(df['date'] + ' ' + df['time'])
df = df.set_index('Datetime')
並擺脫不需要的列(正如 OP 所做的那樣,但沒有在問題中本身指定):
df = df.drop(['date','time'], axis=1)
您沒有正確創建日期時間索引,
format = '%Y-%m-%d %H:%M:%S'
df['Datetime'] = pd.to_datetime(df['date'] + ' ' + df['time'], format=format)
df = df.set_index(pd.DatetimeIndex(df['Datetime']))
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