Jeremy Sanders <jeremy@...> writes:
>
> On 04/05/2013 04:26 AM, Steven hunyady wrote:
>
> > Now I'd like to use embedded Veusz in a python program that captures the
live
> > data itself. I added and modified the embedded example but my lack of
> > knowledge about Veusz and python has me puzzled about how to manipulate
the
> > datasets. I'm currently using ImportString() to get one line of data at
a
> > time (and veusz plots this one point), but I don't know how to append to
this
> > data (instead of replacing it) when the next line is obtained.
>
> You could keep a cumulative string, which you append the new line to,
> and keep passing this to ImportString. However, this is probably much
> less efficient than converting the data to numbers yourself and using
> SetData, e.g.
>
> datax = []
> datay = []
> for line in fileobject:
> parts = line.split()
> datax.append( float(parts[0]) )
> datay.append( float(parts[1]) )
> SetData('x', datax)
> SetData('y', datay)
>
> SetData avoids reconverting the data each time, creating temporary
> copies of the data during parsing, and building up a very long string.
>
> SetData has options for error bars. There is SetData2D for 2D datasets.
>
> Hope this helps
>
> Jeremy
>
Many thanks! I saw this under "Reading other data formats" but now I
understand its value.
My next puzzle is how to plot multiple columns of data. I see how it is done
in the command line interface with a second xy plotter, but that does not
appear to work in the embedded interface. I'll post the code if needed.
Thanks again. -sjh
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