matplotlib-users Mailing List for matplotlib

On Thu, Feb 2, 2012 at 3:52 PM, Jerzy Karczmarczuk <
jer...@un...> wrote:
> Benjamin Root :
> > Just about any mpl plotting function (plot(), scatter(), hist(), etc.)
> > returns an object. Most of the time, users do not save the result
> > into a variable, but if you want to do advanced tricks, you will need
> > to save those returns.
> Sorry for a shameless attempt to add something to this, but actually
> here you don't need it, these collections are accessible through the
> current axes:
>
>
> plt.plot([0, 1, 2, 3, 4], [4, 3, 2, 1, 0])
> pts = plt.scatter([1, 2, 3], [1, 2, 3])
>
> ax=plt.gca()
> ...
> del ax.collections[:]
>
>
I forget if this approach is recommended or not. There are methods for ax
that properly handle removal of types of artists that have been attached to
an axes. The above approach assumes that no other collections have been
plotted that you wanted to keep. The approach I gave is a very surgical
method that makes sure that only what is supposed to be removed gets
removed. Both are valid, and their usefulness depends upon which view of
the data you need (remove types of artists versus removing particular
artists).
> This reminds me a nuisance... Under Windows XP, ion() is not too
> compatible with show().
> TKAgg (by default), WXAgg and GTKAgg bomb Bens program (and without
> draw() nothing is plotted).
>
>
That would be a bug and should be reported (assuming that it is in the
latest version). Make sure that you are using at least v1.0.1 (preferably
v1.1.0) to make sure that show() should do what you want. Any version
earlier than v1.0.1 is very unpredictable with respect to multiple show()
calls.
Ben Root

Benjamin Root :
> Just about any mpl plotting function (plot(), scatter(), hist(), etc.) 
> returns an object. Most of the time, users do not save the result 
> into a variable, but if you want to do advanced tricks, you will need 
> to save those returns.
Sorry for a shameless attempt to add something to this, but actually 
here you don't need it, these collections are accessible through the 
current axes:
plt.plot([0, 1, 2, 3, 4], [4, 3, 2, 1, 0])
pts = plt.scatter([1, 2, 3], [1, 2, 3])
ax=plt.gca()
...
del ax.collections[:]
(Or, say, del ax.lines[:] to remove the first line ; I do it often when 
I plot a solution of a differential equation, a trajectory, keeping just 
a few last segments).
==
This reminds me a nuisance... Under Windows XP, ion() is not too 
compatible with show().
TKAgg (by default), WXAgg and GTKAgg bomb Bens program (and without 
draw() nothing is plotted).
Jerzy Karczmarczuk

On Thu, Feb 2, 2012 at 3:04 PM, G Jones <gle...@gm...> wrote:
> Note there is a typo. Ben assigned the output to "pts" but then referenced
> "res".
>
>
Good catch!
Ben Root

Note there is a typo. Ben assigned the output to "pts" but then referenced
"res".
On Thu, Feb 2, 2012 at 12:59 PM, Benjamin Root <ben...@ou...> wrote:
> On Thu, Feb 2, 2012 at 2:54 PM, Jim St.Cyr <jim...@gm...> wrote:
>
>> On 2/2/2012 3:41 PM, Benjamin Root wrote:
>>
>> On Wed, Feb 1, 2012 at 4:07 PM, Jim St.Cyr <jim...@gm...> wrote:
>>
>>> Hello-
>>>
>>> Scenario:
>>>
>>> Basemap used to display the East Coast of the US and the Atlantic Ocean.
>>> Shapelib is used read a shapefile the contents of is pumped into a PyPlot
>>> subplot hosted Line Collection which overlays the ocean with a grid
>>> PyPlot text is used to label each grid with it's designator.
>>>
>>> What I want to do is plot a collection of points, save the result as a
>>> PNG,
>>> clear the first set of points, plot another collection of points, save
>>> the
>>> result, and so on. The problem is the if I use the Pyplot clf function
>>> it wipes
>>> everything previously built.
>>>
>>> What do I need to do in order to clear just the points without clearing
>>> everything?
>>>
>>> Thank you.
>>>
>>> Jim
>>>
>>>
>> Jim,
>>
>> Sorry for the delay. Most plotting functions in matplotlib returns a
>> Collection object. These objects have a member function "remove()".
>>
>> >>> import matplotlib.pyplot as plt
>> >>> plt.ion()
>> >>> plt.plot([0, 1, 2, 3, 4], [4, 3, 2, 1, 0])
>> >>> pts = plt.scatter([1, 2, 3], [1, 2, 3])
>> >>> plt.show() # You see three points and a line
>> >>> res.remove()
>> >>> plt.show() # Now you see only the line
>>
>>
>> I hope that helps!
>> Ben Root
>>
>> Ben-
>>
>> Very helpful. A question, how do you determine the object designator?
>> In your example above, res.remove(), where did the 'res' come from?
>>
>> Jim
>>
>
> It was assigned when I called scatter(). Just about any mpl plotting
> function (plot(), scatter(), hist(), etc.) returns an object. Most of the
> time, users do not save the result into a variable, but if you want to do
> advanced tricks, you will need to save those returns.
>
> Ben Root
>
>
>
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On Thu, Feb 2, 2012 at 2:54 PM, Jim St.Cyr <jim...@gm...> wrote:
> On 2/2/2012 3:41 PM, Benjamin Root wrote:
>
> On Wed, Feb 1, 2012 at 4:07 PM, Jim St.Cyr <jim...@gm...> wrote:
>
>> Hello-
>>
>> Scenario:
>>
>> Basemap used to display the East Coast of the US and the Atlantic Ocean.
>> Shapelib is used read a shapefile the contents of is pumped into a PyPlot
>> subplot hosted Line Collection which overlays the ocean with a grid
>> PyPlot text is used to label each grid with it's designator.
>>
>> What I want to do is plot a collection of points, save the result as a
>> PNG,
>> clear the first set of points, plot another collection of points, save the
>> result, and so on. The problem is the if I use the Pyplot clf function
>> it wipes
>> everything previously built.
>>
>> What do I need to do in order to clear just the points without clearing
>> everything?
>>
>> Thank you.
>>
>> Jim
>>
>>
> Jim,
>
> Sorry for the delay. Most plotting functions in matplotlib returns a
> Collection object. These objects have a member function "remove()".
>
> >>> import matplotlib.pyplot as plt
> >>> plt.ion()
> >>> plt.plot([0, 1, 2, 3, 4], [4, 3, 2, 1, 0])
> >>> pts = plt.scatter([1, 2, 3], [1, 2, 3])
> >>> plt.show() # You see three points and a line
> >>> res.remove()
> >>> plt.show() # Now you see only the line
>
>
> I hope that helps!
> Ben Root
>
> Ben-
>
> Very helpful. A question, how do you determine the object designator? In
> your example above, res.remove(), where did the 'res' come from?
>
> Jim
>
It was assigned when I called scatter(). Just about any mpl plotting
function (plot(), scatter(), hist(), etc.) returns an object. Most of the
time, users do not save the result into a variable, but if you want to do
advanced tricks, you will need to save those returns.
Ben Root

On 2/2/2012 3:41 PM, Benjamin Root wrote:
> On Wed, Feb 1, 2012 at 4:07 PM, Jim St.Cyr <jim...@gm... 
> <mailto:jim...@gm...>> wrote:
>
> Hello-
>
> Scenario:
>
> Basemap used to display the East Coast of the US and the Atlantic Ocean.
> Shapelib is used read a shapefile the contents of is pumped into a PyPlot
> subplot hosted Line Collection which overlays the ocean with a grid
> PyPlot text is used to label each grid with it's designator.
>
> What I want to do is plot a collection of points, save the result as a PNG,
> clear the first set of points, plot another collection of points, save the
> result, and so on. The problem is the if I use the Pyplot clf function it
> wipes
> everything previously built.
>
> What do I need to do in order to clear just the points without clearing
> everything?
>
> Thank you.
>
> Jim
>
>
> Jim,
>
> Sorry for the delay. Most plotting functions in matplotlib returns a 
> Collection object. These objects have a member function "remove()".
>
> >>> import matplotlib.pyplot as plt
> >>> plt.ion()
> >>> plt.plot([0, 1, 2, 3, 4], [4, 3, 2, 1, 0])
> >>> pts = plt.scatter([1, 2, 3], [1, 2, 3])
> >>> plt.show() # You see three points and a line
> >>> res.remove()
> >>> plt.show() # Now you see only the line
>
>
> I hope that helps!
> Ben Root
>
Ben-
Very helpful. A question, how do you determine the object designator? In your 
example above, res.remove(), where did the 'res' come from?
Jim

On Wed, Feb 1, 2012 at 4:07 PM, Jim St.Cyr <jim...@gm...> wrote:
> Hello-
>
> Scenario:
>
> Basemap used to display the East Coast of the US and the Atlantic Ocean.
> Shapelib is used read a shapefile the contents of is pumped into a PyPlot
> subplot hosted Line Collection which overlays the ocean with a grid
> PyPlot text is used to label each grid with it's designator.
>
> What I want to do is plot a collection of points, save the result as a PNG,
> clear the first set of points, plot another collection of points, save the
> result, and so on. The problem is the if I use the Pyplot clf function it
> wipes
> everything previously built.
>
> What do I need to do in order to clear just the points without clearing
> everything?
>
> Thank you.
>
> Jim
>
>
Jim,
Sorry for the delay. Most plotting functions in matplotlib returns a
Collection object. These objects have a member function "remove()".
>>> import matplotlib.pyplot as plt
>>> plt.ion()
>>> plt.plot([0, 1, 2, 3, 4], [4, 3, 2, 1, 0])
>>> pts = plt.scatter([1, 2, 3], [1, 2, 3])
>>> plt.show() # You see three points and a line
>>> res.remove()
>>> plt.show() # Now you see only the line
I hope that helps!
Ben Root

> Hello!
> 
> How can I zoom exactly on the same region on two different subplots at
> the same time. This option is enable when I use plotfile but not if I
> use plot, and subplots?
> 
> Thx!
> Fabien
Fabien,
When you create the new subplots, add the sharex=ax, sharey=ax keywords, where ax is the first set of axes you create.
-Sterling

Thanks Daryl, it works!
2012年2月2日 Daryl Herzmann <ak...@ia...>:
> On Thu, Feb 2, 2012 at 8:52 AM, Fabien Lafont <laf...@gm...> wrote:
>> I don't manage to put the color of my plot in the argument' list function.
>>
>> Example:
>>
>> def function(color):
>>
>>   plot(x,y,'.', color, label = "this is my curve")
>>
>>
>> function('r')
>>
>> even if I put function(" 'r' ") it doesn't work.
>>
>> Any idea?
>
> I would suggest using named arguments for everything other than x and y, so
>
> plot(x,y,marker=',', color=color, label='this is my curve')
>
> http://matplotlib.sourceforge.net/api/axes_api.html?highlight=plot#matplotlib.axes.Axes.plot
>
> daryl

On Thu, Feb 2, 2012 at 8:52 AM, Fabien Lafont <laf...@gm...> wrote:
> I don't manage to put the color of my plot in the argument' list function.
>
> Example:
>
> def function(color):
>
>   plot(x,y,'.', color, label = "this is my curve")
>
>
> function('r')
>
> even if I put function(" 'r' ") it doesn't work.
>
> Any idea?
I would suggest using named arguments for everything other than x and y, so
plot(x,y,marker=',', color=color, label='this is my curve')
http://matplotlib.sourceforge.net/api/axes_api.html?highlight=plot#matplotlib.axes.Axes.plot
daryl

I don't manage to put the color of my plot in the argument' list function.
Example:
def function(color):
 plot(x,y,'.', color, label = "this is my curve")
function('r')
even if I put function(" 'r' ") it doesn't work.
Any idea?

Thx!
2012年2月2日 Angus McMorland <am...@gm...>:
> On 2 February 2012 08:32, Fabien Lafont <laf...@gm...> wrote:
>> Hello!
>>
>> How can I zoom exactly on the same region on two different subplots at
>> the same time. This option is enable when I use plotfile but not if I
>> use plot, and subplots?
>
> Create the first axes object, then when you create subsequent ones,
> pass the first as the value of the sharex and sharey keywords to the
> subplot or add_axes command.
> See this page [1] for a quick example.
>
> Angus
>
> [1] http://matplotlib.sourceforge.net/users/recipes.html?highlight=sharex%20subplot
>
>> Thx!
>> Fabien
>>
>> ------------------------------------------------------------------------------
>> Keep Your Developer Skills Current with LearnDevNow!
>> The most comprehensive online learning library for Microsoft developers
>> is just 99ドル.99! Visual Studio, SharePoint, SQL - plus HTML5, CSS3, MVC3,
>> Metro Style Apps, more. Free future releases when you subscribe now!
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>> _______________________________________________
>> Matplotlib-users mailing list
>> Mat...@li...
>> https://lists.sourceforge.net/lists/listinfo/matplotlib-users
>
>
>
> --
> AJC McMorland
> Post-doctoral research fellow
> Neurobiology, University of Pittsburgh

On 2 February 2012 08:32, Fabien Lafont <laf...@gm...> wrote:
> Hello!
>
> How can I zoom exactly on the same region on two different subplots at
> the same time. This option is enable when I use plotfile but not if I
> use plot, and subplots?
Create the first axes object, then when you create subsequent ones,
pass the first as the value of the sharex and sharey keywords to the
subplot or add_axes command.
See this page [1] for a quick example.
Angus
[1] http://matplotlib.sourceforge.net/users/recipes.html?highlight=sharex%20subplot
> Thx!
> Fabien
>
> ------------------------------------------------------------------------------
> Keep Your Developer Skills Current with LearnDevNow!
> The most comprehensive online learning library for Microsoft developers
> is just 99ドル.99! Visual Studio, SharePoint, SQL - plus HTML5, CSS3, MVC3,
> Metro Style Apps, more. Free future releases when you subscribe now!
> http://p.sf.net/sfu/learndevnow-d2d
> _______________________________________________
> Matplotlib-users mailing list
> Mat...@li...
> https://lists.sourceforge.net/lists/listinfo/matplotlib-users
-- 
AJC McMorland
Post-doctoral research fellow
Neurobiology, University of Pittsburgh

Hello!
How can I zoom exactly on the same region on two different subplots at
the same time. This option is enable when I use plotfile but not if I
use plot, and subplots?
Thx!
Fabien