Pandas DataFrame 按天/小时/分钟切片
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Pandas DataFrame slicing by day/hour/minute
提问by Vitali Molchan
I have pandas Dataframe with datetime index like 'YYYY-MM-DD HH:MM:SS'.
我有带有日期时间索引的Pandas数据框，如“YYYY-MM-DD HH:MM:SS”。
Index Parameter
2007-05-02 14:14:08 134.8
2007-05-02 14:14:32 134.8
2007-05-02 14:14:41 134.8
2007-05-02 14:14:53 134.8
2007-05-02 14:15:01 134.8
2007-05-02 14:15:09 134.8
......
2007-05-30 23:08:02 105.9
2007-05-30 23:18:02 105.9
2007-05-30 23:28:02 105.9
2007-05-30 23:38:03 105.8
It is possible to get slice a DataFrame by year df['2007']or by month df['2007-05']?
可以按年df['2007']或按月对 DataFrame 进行切片df['2007-05']吗？
But when I've tried to slice DataFrame by day, for example df['2007-05-02'], I've got the error:
但是，例如df['2007-05-02']，当我尝试按天对 DataFrame 进行切片时，出现错误：
KeyError: < Timestamp: 2007-02-05 00:00:00.
I use the pandas version 8.0.1. Is it possible to slice DataFrame with smaller frequency than year or month? For example, by day or hour?
我使用Pandas版本 8.0.1。是否可以以比年或月更小的频率对 DataFrame 进行切片？例如，按天还是按小时？
回答by root
use df.ix[x:y]where xand yare datetime objects.
使用df.ix[x:y]wherex和yare datetime 对象。
Example:
例子：
In [117]: frame.index.summary()
Out[117]: 'DatetimeIndex: 6312960 entries, 2000-04-05 00:01:00 to 2012-04-06 00:00:00\nFreq: T'
In [118]: x=datetime(2001, 4, 5, 0, 1)
In [119]: y=datetime(2001, 4, 5, 0, 5)
In [120]: print frame.ix[x:y]
radiation tamb
2001-04-05 00:01:00 67.958873 8.077386
2001-04-05 00:02:00 50.801294 0.731453
2001-04-05 00:03:00 16.042035 6.944998
2001-04-05 00:04:00 5.678343 9.728967
2001-04-05 00:05:00 72.551601 7.652942
you can also do this:
你也可以这样做：
In [121]: print frame.ix[x]
radiation 67.958873
tamb 8.077386
Name: 2001-04-05 00:01:00
