On 05/16/2010 10:19 AM, Philipp K. Janert wrote:
>
> Let's say I am running an interactive session
> (ipython -pylab), and now issue the following
> commands:
>
> x = linspace(0, 10, 100 )
> plot( x, sin(x) )
> ylim( -2, 2 )
> plot( x, cos(x) )
>
> Then the second plot command seems to reset
> the plot limits to [-1,1] - which makes sense for
> the figure, but is not what I requested.
>
> Is this behavior intended? It seems odd to me,
> since generally matplotlib seems to retain state
> that has between invocations of plot().
Good question. The control of autoscaling has a somewhat clunky
interface via Axes methods, and via the plot function. Your two options
are to follow the ylim call with the ugly
gca().set_autoscaley_on(False)
or to add a kwarg to all subsequent plot calls:
plot(x, cos(x), scaley=False)
A possible mpl improvement would be to add a kwarg to the pyplot.ylim
and xlim functions, e.g.
ylim(-2, 2, keep=True)
Calling the kwarg "hold" would read better to my eye, but would conflict
with the use of "hold" to mean "keep all prior plot elements". Maybe
there is a better name, e.g. setting "auto=False" to mean "don't
autoscale this on the next plot command". Or "save=True". I suspect we
would have to leave the default behavior as it is for continuity and
backwards compatibility, although I think that changing it would be an
improvement overall.
Eric
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