Thread: [Matplotlib-users] inconsistency in LineCollection

Hello -
I got confused about specifying colors and linewidths for LineCollections.
I think it would be helpful if the docstrings explicitly state that they
should be sequences.
I know, they do in some way, but it i
Maybe we should even check this on input, as the error message you get when
you don't do that is confusing.
Let me explain:
from pylab import *
from matplotlib.collections import LineCollection
ax = subplot(111)
ax.add_collection( LineCollection( [[(0,0),(1,1)]], colors='r' ) )
draw()
This works fine, as apparantly colors='r' is interpreted as a sequence.
This does not work, however:
ax.add_collection( LineCollection( [[(0,0),(1,1)]], colors='r', linewidths=2
) )
draw()
Now I get an error: TypeError: CXX: type error. That's not too helpful.
What does work is
ax.add_collection( LineCollection( [[(0,0),(1,1)]], colors='r',
linewidths=[2] ) )
draw()
Maybe the confusing part is that just specifying colors='r' works.
Thanks,
Mark
ps. I do all the draws as I am in interactive mode.

On 10/31/07, Mark Bakker <ma...@gm...> wrote:
> This works fine, as apparantly colors='r' is interpreted as a sequence.
> This does not work, however:
>
> ax.add_collection( LineCollection( [[(0,0),(1,1)]], colors='r', linewidths=2
> ) )
> draw()
>
> Now I get an error: TypeError: CXX: type error. That's not too helpful.
This is fixed in svn -- now collection properties should work with a
scalar or iterable so if you find more problems, let us know.
JDH