[Matplotlib-users] overridding builtin variables in pylab

[Andrew S. <str...@as...>]

A few weeks ago (on Dec 18), I send an email to the matplotlib-devel 
list indicating that "from pylab import *" overrides some builtin 
functions, such as min() and max(). [1]

This results from pylab enlarging its namespace greatly with statements 
like "from numerix import *" and "from mlab import *".  In general this 
is a good thing, but it seems numarray.linear_algebra.mlab (amongst 
possibly others) overrides some builtin names.  Although I don't see the 
benefit in this design for numarray.linear_algebra.mlab, I can live with 
it, since I never do "from numarray.linear_algebra.mlab import *". 

However, I (and many others here, I suspect) would like to frequently 
use "from pylab import *", and it really pisses me off when I discover 
that various builtins are overridden, causing mysterious errors that may 
be hard to track down.

So, I offer the following patch [2] to pylab.py which fixes this. I 
hereby ask for your feedback indicating if you are happy with the 
current behavior, or if you prefer that pylab does not override 
builtins. (Also, if you have a better way, that would be appreciated, too.)

You may check your own systems using a little script I wrote while 
testing this. [3]

Cheers!
Andrew

[1] 
http://sourceforge.net/mailarchive/forum.php?thread_id=6190717&forum_id=36187

[2] Patch to pylab.py, to be inserted anywhere after the last "from blah 
import *", e.g. line 216.

# restore builtin functions which may have been overridden
min = getattr(sys.modules['__builtin__'],'min')
max = getattr(sys.modules['__builtin__'],'max')
sum = getattr(sys.modules['__builtin__'],'sum')
round = getattr(sys.modules['__builtin__'],'round')
abs = getattr(sys.modules['__builtin__'],'abs')

[3] Script to test for overriding of builtin names:

import sys

def check_globals():
    for key in globals().keys():
        if key in dir(sys.modules['__builtin__']):
            if globals()[key] != getattr(sys.modules['__builtin__'],key):
                print "'%s' was overridden in globals()."%key

print 'before pylab import'
check_globals()
print

from pylab import *

print 'after pylab import'
check_globals()
print