Hi John,
very very interesting idea.
Is there a way to add some extras informations on the records arrays columns,
like the units or/and the desired labels for the resulting plotted lines,
directly retrieved in the CSV files?
Cordialy
Le jeudi 07 juin 2007, John Hunter a écrit :
> I just added support for native plotting of python date and datetime
> objects (you still can, but don't have to use plot_date with date2num
> conversions). We will continue to do conversion to floats under the
> hood, but the conversion can be handled automagically. I also added
> support for loading CSV files (or general space/tab/comma delimited
> files) into numpy record arrays, and the type conversions (int, float,
> date, etc...) happen automagically. The function assumes there is a
> header row, and these strings will be munged to give valid python
> attribute names. It inspects the first checkrows lines after the
> header to try and infer the datatype and set the appropriate
> conversion function. It's not entirely bullet proof, but it should
> cover a lot of common use cases.
>
> Here is an example (svn only)
>
> from matplotlib.mlab import csv2rec
> from pylab import figure, show
>
> a = csv2rec('data/msft.csv')
> fig = figure()
> ax = fig.add_subplot(111)
> ax.plot(a.date, a.adj_close, '-')
> fig.autofmt_xdate()
> show()
>
> The autofmt_xdate is optional, but is a new function that does a few
> things you usually want in date plots: turns off tick labels in the
> upper subplots if any, rotates the tick labels on the lowest axes and
> right aligns them, and increases the bottom of the subplots adjust to
> make room for the rotated tick labels.
>
> Here is what the dtype looks like from the example above.
>
> In [3]: !head -3 data/msft.csv
> Date,Open,High,Low,Close,Volume,Adj. Close*
> 19-Sep-03,29.76,29.97,29.52,29.96,92433800,29.79
> 18-Sep-03,28.49,29.51,28.42,29.50,67268096,29.34
>
> In [4]: a = csv2rec('data/msft.csv')
>
> In [5]: a.dtype
> Out[5]: dtype([('date', '|O4'), ('open', '<f8'), ('high', '<f8'),
> ('low', '<f8'), ('close', '<f8'), ('volume', '<i4'), ('adj_close',
> '<f8')])
>
> In [6]: a.date[:2]
> Out[6]: array([2003-09-19 00:00:00, 2003-09-18 00:00:00], dtype=object)
>
> I'll probably add a few performance features to the csv2rec function,
> mainly to let you skip columns and supply conversion functions where
> desired because the autodate parser is pretty slow if you want to
> parse date strings, but this is enough to make it useful. Another
> useful feature will be able to support customizable type dependent
> NULL value conversion (eg convert to numpy.nan for floats,
> '0000-00-00' for dates, etc...)
>
> Record arrays are your friend; have fun!
> JDH
>
> -------------------------------------------------------------------------
> This SF.net email is sponsored by DB2 Express
> Download DB2 Express C - the FREE version of DB2 express and take
> control of your XML. No limits. Just data. Click to get it now.
> http://sourceforge.net/powerbar/db2/
> _______________________________________________
> Matplotlib-users mailing list
> Matplotlib-users@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/matplotlib-users
--
Lionel Roubeyrie - [EMAIL PROTECTED]
Chagé d'études et de maintenance
LIMAIR - la Surveillance de l'Air en Limousin
http://www.limair.asso.fr
-------------------------------------------------------------------------
This SF.net email is sponsored by DB2 Express
Download DB2 Express C - the FREE version of DB2 express and take
control of your XML. No limits. Just data. Click to get it now.
http://sourceforge.net/powerbar/db2/
_______________________________________________
Matplotlib-users mailing list
Matplotlib-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/matplotlib-users
