按日期/小时/分钟对Pandas DataFrame进行切片 [英] Pandas DataFrame slicing by day/hour/minute

问题描述

我有日期时间索引为"YYYY-MM-DD HH:MM:SS"的熊猫数据框.

I have pandas Dataframe with datetime index like '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 

是否可以按年份df['2007']或按月份df['2007-05']分割DataFrame?

It is possible to get slice a DataFrame by year df['2007'] or by month df['2007-05']?

但是当我尝试按天对DataFrame进行切片时，例如df['2007-05-02']，我得到了错误:

But when I've tried to slice DataFrame by day, for example df['2007-05-02'], I've got the error:

KeyError: < Timestamp: 2007-02-05 00:00:00. 

我使用的是熊猫8.0.1版.是否可以以比年或月小的频率对DataFrame进行切片?例如，按天还是按小时?

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?

推荐答案

使用df.ix[x:y]，其中x和y是日期时间对象.

use df.ix[x:y] where x and y are datetime objects.

示例:

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

您也可以这样做:

In [121]: print frame.ix[x]
radiation    67.958873
tamb          8.077386
Name: 2001-04-05 00:01:00

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