Re: changing local namespace of a function

[Bo Peng]

Kent Johnson wrote:
Bo Peng wrote:
Exec is slow since compiling the string and calls to globals() use a 
lot of time.  The last one is most elegant but __getattr__ and 
__setattr__ are costly. The 'evil hack' solution is good since 
accessing x and y takes no additional time.

Previous comparison was not completely fair since I could pre-compile 
fun2 and I used indirect __setattr__. Here is the new one:
 >>> # solution two: use exec
... def makeFunction(funcStr, name):
...   code = compile(funcStr, name, 'exec')
...   def f(d):
...     exec code in d
...   return f
...
 >>> def fun2(d):
...   myfun = makeFunction('z = x + y', 'myfun')
...   for i in xrange(0,N):
...     myfun(d)
...   del d['__builtins__']

You are still including the compile overhead in fun2. If you want to see 
how fast the compiled code is you should take the definition of myfun 
out of fun2:

myfun = makeFunction('z = x + y', 'myfun')
def fun2(d):
  for i in xrange(0,N):
    myfun(d)
  del d['__builtins__']
Kent
I assumed that most of the time will be spent on N times execution of 
myfunc.

>>> myfun = makeFunction('z = x + y', 'myfun')
>>> def fun2(d):
...   # myfun = makeFunction('z = x + y', 'myfun')
...   for i in xrange(0,N):
...     myfun(d)
...   del d['__builtins__']
>>> def fun21(d):
...   myfun = makeFunction('z = x + y', 'myfun')
...   for i in xrange(0,N):
...     myfun(d)
...   del d['__builtins__']
>>> profile.run('fun2(a)')
         200003 function calls in 1.930 CPU seconds
   Ordered by: standard name
   ncalls  tottime  percall  cumtime  percall filename:lineno(function)
        1    0.000    0.000    1.930    1.930 <string>:1(?)
   100000    0.460    0.000    0.460    0.000 myfun:1(?)
        1    0.000    0.000    1.930    1.930 profile:0(fun2(a))
        0    0.000             0.000          profile:0(profiler)
   100000    0.980    0.000    1.440    0.000 python-162616Io.py:4(f)
        1    0.490    0.490    1.930    1.930 python-16261Ud0.py:1(fun2)
>>> profile.run('fun21(a)')
         200004 function calls in 1.920 CPU seconds
   Ordered by: standard name
   ncalls  tottime  percall  cumtime  percall filename:lineno(function)
        1    0.000    0.000    1.920    1.920 <string>:1(?)
   100000    0.390    0.000    0.390    0.000 myfun:1(?)
        1    0.000    0.000    1.920    1.920 profile:0(fun21(a))
        0    0.000             0.000          profile:0(profiler)
        1    0.000    0.000    0.000    0.000 
python-162616Io.py:2(makeFunction)
   100000    0.930    0.000    1.320    0.000 python-162616Io.py:4(f)
        1    0.600    0.600    1.920    1.920 python-16261huu.py:1(fun21)
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