gnuplot-py-users

[Gnuplot-py-users] Example for PlotItem is missing

[Andreas T. <ti...@rk...>]

Hello,

I just tried Gnuplot-py and regard it very valu to solce a certain job.

Unfortunately I have real trouble using PlotItem.  The documentation says:

   For the finest control over the output, you can create PlotItems
   yourself with additional keyword options, or derive new classes
   from PlotItem.

But as a Python beginner I seem to have trouble to understand the
syntax.  I started with a fairly simple example:


#!/usr/bin/python

import Gnuplot, Gnuplot.funcutils

X = []
Y = []
for x in range(32):
   X.append((x, 2*x ))
   Y.append((x, 3*x ))

g = Gnuplot.Gnuplot(debug=1)

g.plot(X, Y)
raw_input('Please press return to continue...\n')


Now I wanted to use PlotItem objects for X and Y to get finer control about
titles and style because the quite simple 2*x and 3*x will be replaced by
some more sophisticated database queries and further plots will be added.

But I do really not understand how to instantiate PlotItems and there
is no example available.

Could you please provide some simple examples?

Thanks for this fine software

          Andreas.

PS: I'm not yet subscribed to this list and would be happy about a CC
    because a list archive does not seem to be available.

Re: [Gnuplot-py-users] Example for PlotItem is missing

[Michael H. <hag...@jp...>]

Andreas Tille writes:
> Unfortunately I have real trouble using PlotItem.

For just setting tables and line types and stuff you don't have to
extend the PlotItem interface directly; you can use the Data class
which is a type of PlotItem already customized for array data.

There are many examples in demo.py about how to use the Data class.
For example,

    x = arange(10, typecode=Float)
    y1 = x**2
    d = Gnuplot.Data(x, y1,
                     title='calculated by python',
                     with='points 3 3')

So for your example,

> #!/usr/bin/python
> 
> import Gnuplot, Gnuplot.funcutils
> 
> X = []
> Y = []
> for x in range(32):
>    X.append((x, 2*x ))
>    Y.append((x, 3*x ))
> 
> g = Gnuplot.Gnuplot(debug=1)
> 
> g.plot(X, Y)
> raw_input('Please press return to continue...\n')

You would do something like the following (untested):

g.plot(
    Gnuplot.Data(X, title='This is the X dataset', with='linespoints'),
    Gnuplot.Data(Y, title='Some more data', with='points 2 5'),
    )

> PS: I'm not yet subscribed to this list and would be happy about a CC
>     because a list archive does not seem to be available.

Please subscribe.  The list has an archive but since the list is very
new there are only a few messages in it.

Michael

--
Michael Haggerty
hag...@jp...

Re: [Gnuplot-py-users] Example for PlotItem is missing

[Andreas T. <ti...@rk...>]

On Wed, 14 Aug 2002, Michael Haggerty wrote:

> For just setting tables and line types and stuff you don't have to
> extend the PlotItem interface directly; you can use the Data class
> which is a type of PlotItem already customized for array data.
>
> There are many examples in demo.py about how to use the Data class.
> For example,
>
>     x = arange(10, typecode=Float)
>     y1 = x**2
>     d = Gnuplot.Data(x, y1,
>                      title='calculated by python',
>                      with='points 3 3')
Ahh, now this is clear.  I just was 'grep'ing for PlotItem and did not
found this keyword.  The reason is that I'm quite a Python beginner, sorry.

> You would do something like the following (untested):
>
> g.plot(
>     Gnuplot.Data(X, title='This is the X dataset', with='linespoints'),
>     Gnuplot.Data(Y, title='Some more data', with='points 2 5'),
>     )
I've got the point now.

Thanks for this fine software!

> Please subscribe.  The list has an archive but since the list is very
> new there are only a few messages in it.
I'll do so for my next question ;-).  The amount of lists I'm subscribed
is quite high but if this is a low volume list I can cope with this.

Kind regards

        Andreas.