matplotlib-users

[Matplotlib-users] Newbie question about plotting multiple lines

[Ryugan M. <ryu...@sb...>]

Hi all,

I'm trying to create multiple lines on one graph.  Anybody have an idea =
of plotiing multiple lines without writing the plot statement a number =
of times?  Is it possible to include the plot statement inside a "for" =
statement to produce multiple lines in one graph???


Thanks.

Ryugan

Re: [Matplotlib-users] Newbie question about plotting multiple lines

[Darren D. <dd...@co...>]

Ryugan Mizuta wrote:

> Hi all,
>  
> I'm trying to create multiple lines on one graph.  Anybody have an 
> idea of plotiing multiple lines without writing the plot statement a 
> number of times?  Is it possible to include the plot statement inside 
> a "for" statement to produce multiple lines in one graph???
>  
>  

Hi Ryugan,

There are a lot of ways to do this, I dont know them all. Here are a few 
to get you started:

from matplotlib.matlab import *

a=arange(10)
b=a*2
c=a*3
figure(1)
plot(a,b,a,c)
figure(2)
plot(a,b,'k',a,c,'r')

figure(3)
[plot(a,i) for i in [b,c]]
#equivalent to:
figure(4)
for i in [b,c]:
    plot(a,i)

Re: [Matplotlib-users] Newbie question about plotting multiple lines

[John H. <jdh...@ac...>]

>>>>> "Darren" == Darren Dale <dd...@co...> writes:


    Darren> There are a lot of ways to do this, I dont know them
    Darren> all. Here are a few to get you started:

These are all good suggestions, and the right way 99% of the time.  I
just want to point out that if you need to plot hundreds or thousands
of separate lines, calling plot over and over again is not the most
efficient strategy, since a new matplotlib.lines.Line2D object must be
created each time.  For these cases it is best to use a line
collection (matplotlib.collections.LineCollection).  You can find an
example of their use in the plotmap demo -
http://matplotlib.sourceforge.net/screenshots.html#plotmap, where line
collections are used to draw the geographic borders over a colormap.

JDH

Re[2]: [Matplotlib-users] Newbie question about plotting multiple lines

[Alan G I. <ai...@am...>]

On Wed, 08 Sep 2004, Darren Dale apparently wrote:
> from matplotlib.matlab import *
> figure(3)
> [plot(a,i) for i in [b,c]]
> #equivalent to:
> figure(4)
> for i in [b,c]:
>     plot(a,i)


These two examples suggest that one
ought to be able to input 2D arrays
for plotting against a 1D array.
(As in, e.g., GAUSS's xy() command.)

fwiw,
Alan Isaac