Thread: [Matplotlib-users] Why is wrapper module called "pylab" ?

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So is matplotlib the name of the low level plotting engine?

And, pylab is the user-friendly wrapper?

Would it be ok to call the whole system "Pylab" instead of Matplotlib then?

Chris

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ch...@se... ha scritto:
> So is matplotlib the name of the low level plotting engine?
> 
> And, pylab is the user-friendly wrapper?
> 
> Would it be ok to call the whole system "Pylab" instead of Matplotlib then?

Personally I'd say "no" exactly because they are two different things,
as you correctly pointed out.

m.
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Pylab is just a name for a module in matplotlib that is supposed to mimic
matlab.  I would say its intent it to ease the transition for matlab users.
 It wouldn't really make sense to refer to matplotlib as pylab.  The
matplotlib.pyplot is favored over the pylab module now.
- Charlie

On Sun, Oct 26, 2008 at 1:28 AM, <ch...@se...> wrote:

>
> So is matplotlib the name of the low level plotting engine?
>
> And, pylab is the user-friendly wrapper?
>
> Would it be ok to call the whole system "Pylab" instead of Matplotlib then?
>
>
> Chris
>
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On Sun, Oct 26, 2008 at 11:51:48AM -0400, Charlie Moad wrote:
> The matplotlib.pyplot is favored over the pylab module now.

Thanks!  I find your comment very interesting.  As I have negligible experience
with Matlab, I'd love to use matplotlib.pyplot.

The problem is all the docs use pylab right?  Where find matplotlib.pyplot
examples?

Chris

They're the same plotting interface, just different names.  Pylab pulls in a
few extra functions that aren't specific to plotting, but aid in providing
matlab-alike functionality.  To use matplotlib.pyplot instead of pylab for
any of the examples, just replace lines of:

    import pylab

with:

    import matplotlib.pyplot

Ryan

On Sun, Oct 26, 2008 at 11:29 AM, <ch...@se...> wrote:

> On Sun, Oct 26, 2008 at 11:51:48AM -0400, Charlie Moad wrote:
> > The matplotlib.pyplot is favored over the pylab module now.
>
> Thanks!  I find your comment very interesting.  As I have negligible
> experience
> with Matlab, I'd love to use matplotlib.pyplot.
>
> The problem is all the docs use pylab right?  Where find matplotlib.pyplot
> examples?
>
> Chris
>
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> This SF.Net email is sponsored by the Moblin Your Move Developer's
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> Build the coolest Linux based applications with Moblin SDK & win great
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-- 
Ryan May
Graduate Research Assistant
School of Meteorology
University of Oklahoma

Ryan May wrote:
> They're the same plotting interface, just different names.  Pylab pulls 
> in a few extra functions that aren't specific to plotting, but aid in 
> providing matlab-alike functionality.  To use matplotlib.pyplot instead 
> of pylab for any of the examples, just replace lines of:
> 
>     import pylab
> 
> with:
> 
>     import matplotlib.pyplot

Not quite--the above, taken literally, will not actually work.

To elaborate: pyplot provides a matlab-style state-machine interface to 
the underlying object-oriented interface in matplotlib.  Pylab lumps 
pyplot together with numpy in a single namespace, making that namespace 
(or environment) even more matlab-like, particularly if one uses the 
ipython shell with the "-pylab" option, which imports everything from pylab.

Regarding matplotlib examples: we have been gradually converting them 
from pure matlab-style, using "from pylab import *", to a preferred 
style in which pyplot is used for some convenience functions, either 
pyplot or the object-oriented style is used for the remainder of the 
plotting code, and numpy is used explicitly for numeric array operations.

In this preferred style, the imports at the top are:

import matplotlib.pyplot as plt
import numpy as np

Then one calls, for example, np.arange, np.zeros, np.pi, plt.figure, 
plt.plot, plt.show, etc.

Example, pure matlab-style:

from pylab import *
x = arange(0, 10, 0.2)
y = sin(x)
plot(x, y)
show()

Now in preferred style, but still using pyplot interface:

import matplotlib.pyplot as plt
import numpy as np
x = np.arange(0, 10, 0.2)
y = np.sin(x)
plt.plot(x, y)
plt.show()

And using pyplot convenience functions, but object-orientation for the rest:
import matplotlib.pyplot as plt
import numpy as np
x = np.arange(0, 10, 0.2)
y = np.sin(x)
fig = plt.figure()
ax = fig.add_subplot(111)
ax.plot(x, y)
plt.show()

So, why do all the extra typing required as one moves away from the pure 
matlab-style?  For very simple things like this example, the only 
advantage is educational: the wordier styles are more explicit, more 
clear as to where things come from and what is going on.  For more 
complicated applications, the explicitness and clarity become 
increasingly valuable, and the richer and more complete object-oriented 
interface will likely make the program easier to write and maintain.

Eric

> 
> Ryan
> 
> On Sun, Oct 26, 2008 at 11:29 AM, <ch...@se... 
> <mailto:ch...@se...>> wrote:
> 
>     On Sun, Oct 26, 2008 at 11:51:48AM -0400, Charlie Moad wrote:
>      > The matplotlib.pyplot is favored over the pylab module now.
> 
>     Thanks!  I find your comment very interesting.  As I have negligible
>     experience
>     with Matlab, I'd love to use matplotlib.pyplot.
> 
>     The problem is all the docs use pylab right?  Where find
>     matplotlib.pyplot
>     examples?
> 
>     Chris
> 
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> 
> 
> 
> -- 
> Ryan May
> Graduate Research Assistant
> School of Meteorology
> University of Oklahoma
> 
> 
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> 
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> 
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