Python 如何在数据框中正确设置 Pandas 日期时间对象的日期时间索引？
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/27032052/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
How do I properly set the Datetimeindex for a Pandas datetime object in a dataframe?
提问by user3654387
I have a pandas dataframe:
我有一个熊猫数据框：
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
For which I am trying to convert the df['date'] and df['time'] columns into a datetime. I can do:
为此，我试图将 df['date'] 和 df['time'] 列转换为日期时间。我可以：
df['Datetime'] = pd.to_datetime(df['date']+df['time'])
df = df.set_index(['Datetime'])
del df['date']
del df['time']
And I get:
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
But then if I try:
但是如果我尝试：
df.between_time(time(1),time(22,59,59))['lng'].std()
I get an error - 'TypeError: Index must be DatetimeIndex'
我收到一个错误 - 'TypeError: Index must be DatetimeIndex'
So, I've also tried setting the DatetimeIndex:
所以，我也试过设置 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']
And this throws an error also - 'DateParseError: unknown string format'
这也会引发错误 - 'DateParseError: unknown string format'
How do I create the datetime column and DatetimeIndex correctly so that df.between_time() works right?
如何正确创建日期时间列和 DatetimeIndex 以便 df.between_time() 正常工作？
采纳答案by Kracit
To simplify Kirubaharan's answer a bit:
为了简化基鲁巴哈兰的回答：
df['Datetime'] = pd.to_datetime(df['date'] + ' ' + df['time'])
df = df.set_index('Datetime')
And to get ride of unwanted columns (as OP did but did not specify per se in the question):
并摆脱不需要的列（正如 OP 所做的那样，但没有在问题中本身指定）：
df = df.drop(['date','time'], axis=1)
回答by Kirubaharan J
You are not creating datetime index properly,
您没有正确创建日期时间索引，
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']))
