pandas，python - 如何在时间序列中选择特定时间
问题描述
我现在工作了很长时间，使用 python 和 pandas 分析一组每小时数据，发现它非常好(来自 Matlab.)
I worked now for quite some time using python and pandas for analysing a set of hourly data and find it quite nice (Coming from Matlab.)
现在我有点卡住了.我像这样创建了我的 DataFrame:
Now I am kind of stuck. I created my DataFrame like that:
SamplingRateMinutes=60
index = DateRange(initialTime,finalTime, offset=datetools.Minute(SamplingRateMinutes))
ts=DataFrame(data, index=index)
我现在要做的是在 10 点到 13 点和 20 点到 23 点选择所有日期的数据，以使用这些数据进行进一步计算.到目前为止，我使用
What I want to do now is to select the Data for all days at the hours 10 to 13 and 20-23 to use the data for further calculations. So far I sliced the data using
selectedData=ts[begin:end]
而且我肯定会得到某种脏循环来选择所需的数据.但是必须有一种更优雅的方式来准确索引我想要的内容.我确信这是一个常见问题，伪代码中的解决方案应该是这样的:
And I am sure to get some kind of dirty looping to select the data needed. But there must be a more elegant way to index exacly what I want. I am sure this is a common problem and the solution in pseudocode should look somewhat like that:
myIndex=ts.index[10<=ts.index.hour<=13 or 20<=ts.index.hour<=23]
selectedData=ts[myIndex]
提到我是一名工程师，而不是程序员:) ...然而
To mention I am an engineer and no programer :) ... yet
解决方案
这里有一个例子可以满足你的需求:
Here's an example that does what you want:
In [32]: from datetime import datetime as dt
In [33]: dr = p.DateRange(dt(2009,1,1),dt(2010,12,31), offset=p.datetools.Hour())
In [34]: hr = dr.map(lambda x: x.hour)
In [35]: dt = p.DataFrame(rand(len(dr),2), dr)
In [36]: dt
Out[36]:
<class 'pandas.core.frame.DataFrame'>
DateRange: 17497 entries, 2009-01-01 00:00:00 to 2010-12-31 00:00:00
offset: <1 Hour>
Data columns:
0 17497 non-null values
1 17497 non-null values
dtypes: float64(2)
In [37]: dt[(hr >= 10) & (hr <=16)]
Out[37]:
<class 'pandas.core.frame.DataFrame'>
Index: 5103 entries, 2009-01-01 10:00:00 to 2010-12-30 16:00:00
Data columns:
0 5103 non-null values
1 5103 non-null values
dtypes: float64(2)
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