[Numpy-discussion] newbie: attempt at data frame

Vincent Nijs v-nijs at kellogg.northwestern.edu
Thu Dec 28 13:40:12 CST 2006


Thanks for the input Eike.

I will add load and store methods to Pickle/UnPickle the object. I have got
to get the data into the class first however from an ascii file (txt or
csv).

I'd like to read the data and variable names directly from a single csv
file. I tried this through the python csv module but it would read all data
as strings and I couldn't figure out how to easily separate the variable
names and the data. I you have any suggestion on how I might do this please
let me know.

Unfortunately I don't know what a 'set' method is or would do :) Could you
point to an example perhaps.

I like your ideas for extending the class. I'll look into that when I get
the basic class working.

Best,

Vincent


On 12/28/06 12:54 PM, "Eike Welk" <eike.welk at gmx.net> wrote:

> If your main concern is to store scientific data on disk you might
> try: 
> http://www.pytables.org/moin
> 
> However, it uses numarray internally and a C library, which you have
> to build from source. (You use a Mac right?)
> 
> 
> Concerning your code:
> - Your two file solution seems impractical to me. I think you should
> just pickle your whole dbase object.
> - Maybe you should write 'load' and 'store' methods that create the
> temporary file, Pickler and Unpickler objects.
> -The __init__ method should then construct the object from a list of
> variable names and an array.
> -Offcourse you need a set method.
> 
> more ideas:
> - A special variable name 'time'. Then you can implement a
> getAtTime( varNameList, timePoint) method with interpolation.
> - A 'plot' method that works like matplotlib's plot function.
> - An extract(varNameList) method, that returns a new dbase object with
> only the selected variables.
> - A companion class that can hold several time series at once to
> compare different experiments.
> 
> Finally, post the code to the mailing list. At least I would like to
> use such a class :-).
> 
> Yours
> Eike.
> 
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> 

-- 
Vincent R. Nijs
Assistant Professor of Marketing
Kellogg School of Management, Northwestern University
2001 Sheridan Road, Evanston, IL 60208-2001
Phone: +1-847-491-4574 Fax: +1-847-491-2498
E-mail: v-nijs at kellogg.northwestern.edu
Skype: vincentnijs





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