Filter Time Series with Dates
Get the temperature for given dates using WeatherData. Create a new time series with specified MissingDataMethod to fill in missing data.
In[1]:=
![Click for copyable input](assets.en/filter-time-series-with-dates/In_93.png)
data = TimeSeries[
WeatherData["Chicago",
"Temperature", {{2015, 1, 1}, {2015, 12, 31}}],
MissingDataMethod -> "Interpolation"]
Out[1]=
![](assets.en/filter-time-series-with-dates/O_49.png)
In[2]:=
![Click for copyable input](assets.en/filter-time-series-with-dates/In_94.png)
DateListPlot[data, FrameLabel -> Automatic]
Out[2]=
![](assets.en/filter-time-series-with-dates/O_50.png)
Use MinFilter with one-month range to analyze when the last and first freeze occurred that year.
In[3]:=
![Click for copyable input](assets.en/filter-time-series-with-dates/In_95.png)
minF = MinFilter[data, Quantity[1, "Month"]];
show complete Wolfram Language input
Out[5]=
![](assets.en/filter-time-series-with-dates/O_51.png)
First day after last spring freeze.
In[6]:=
![Click for copyable input](assets.en/filter-time-series-with-dates/In_98.png)
spring = TimeSeriesWindow[minF, {"15 April 2015", "15 May 2015"}];
In[7]:=
![Click for copyable input](assets.en/filter-time-series-with-dates/In_99.png)
DateObject[
First@FirstCase[
spring["Path"], _?(#[[2]] > Quantity[0, "DegreesCelsius"] &)]]
Out[7]=
![](assets.en/filter-time-series-with-dates/O_52.png)
First fall freeze.
In[8]:=
![Click for copyable input](assets.en/filter-time-series-with-dates/In_100.png)
fall = TimeSeriesWindow[minF, {"1 Oct 2015", "31 Oct 2015"}];
In[9]:=
![Click for copyable input](assets.en/filter-time-series-with-dates/In_101.png)
DateObject[
First@FirstCase[
fall["Path"], _?(#[[2]] <= Quantity[0, "DegreesCelsius"] &)]]
Out[9]=
![](assets.en/filter-time-series-with-dates/O_53.png)