|  | dynamically adding some of one module's functions to another | | |
| | | Gabriel Rossetti |  |
|  Posted: Tue Aug 26, 2008 12:41 pm Post subject: dynamically adding some of one module's functions to another |  |
| |  | |
Hello everyone,
I'm trying to import some modules into another's namespace (network_utils)
network_utils.py:
import utils
import constants as main_const
from services import constants as srv_const
from plugins import constants as plg_const
#
# Import all the message creation functions
#
f = dict([ (f, eval("utils." + f)) for f in dir(utils) if
f.startswith("create") ])
__builtins__.update(f)
del utils
#
# Create a virgin namespace
#
class constants:
"""
An aggragation of L{constants},
L{services.constants}, &
L{plugins.constants}
"""
pass
#
# Import all the constants into the new namespace
#
f = dict([ (f, eval("main_const." + f)) for f in dir(main_const) if
f.isupper() ])
constants.__dict__.update(f)
del main_const
f = dict([ (f, eval("srv_const." + f)) for f in dir(srv_const) if
f.isupper() ])
constants.__dict__.update(f)
del srv_const
f = dict([ (f, eval("plg_const." + f)) for f in dir(plg_const) if
f.isupper() ])
constants.__dict__.update(f)
del plg_const
now, if I import network_utils somewhere, and try to call
network_utils.myFunction() I get :
| Quote: | import network_utils
network_utils.myFunction
Traceback (most recent call last): |
File "<console>", line 1, in <module>
AttributeError: 'module' object has no attribute 'myFunction'
but if I try to access the constants class:
| Quote: | from network_utils import constants
constants.NO_DATA_TYPE
'none' |
it works, how come?
Thank you,
Gabriel |
| |
| | | Bruno Desthuilliers | |
| | Posted: Tue Aug 26, 2008 5:42 pm Post subject: Re: dynamically adding some of one module's functions to ano | |
| | | |
Gabriel Rossetti a écrit :
| Quote: | Hello everyone,
I'm trying to import some modules into another's namespace (network_utils)
network_utils.py:
import utils
import constants as main_const
from services import constants as srv_const
from plugins import constants as plg_const
#
# Import all the message creation functions
#
f = dict([ (f, eval("utils." + f)) for f in dir(utils) if
f.startswith("create") ])
|
As usual, you don't need eval here. Use getattr instead:
create_functions = dict(
(name, getattr(utils, name)
for name in dir(utils)
if name.startswith('create')
)
| Quote: | __builtins__.update(f)
|
Python 2.5.1 (r251:54863, Apr 6 2008, 17:20:35)
[GCC 4.1.2 (Gentoo 4.1.2 p1.0.2)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
| Quote: | __builtins__
module '__builtin__' (built-in)
type(__builtins__)
type 'module'
__builtins__.update
Traceback (most recent call last): |
File "<stdin>", line 1, in <module>
AttributeError: 'module' object has no attribute 'update'
Anyway, adding to builtins is certainly not the best thing to do. I
don't know what you're trying to do here, but looks like a very ugly
mess to me.
| Quote: | del utils
#
# Create a virgin namespace
#
class constants:
"""
An aggragation of L{constants},
L{services.constants}, &
L{plugins.constants}
"""
pass
|
| Quote: | #
# Import all the constants into the new namespace
#
f = dict([ (f, eval("main_const." + f)) for f in dir(main_const) if
f.isupper() ])
constants.__dict__.update(f)
del main_const
f = dict([ (f, eval("srv_const." + f)) for f in dir(srv_const) if
f.isupper() ])
constants.__dict__.update(f)
del srv_const
f = dict([ (f, eval("plg_const." + f)) for f in dir(plg_const) if
f.isupper() ])
constants.__dict__.update(f)
del plg_const
|
Yuck.
In your constants.py file, just add the relevant imports:
from services.constants import *
from plugins.constants import *
And then in your network_utils file:
import constants
But this is still a mess to me. The nice point with explicit import and
modules namespaces is that you at least have a chance to know where a
given symbol comes from.
| Quote: |
now, if I import network_utils somewhere, and try to call
network_utils.myFunction() I get :
import network_utils
network_utils.myFunction
Traceback (most recent call last):
File "<console>", line 1, in <module
AttributeError: 'module' object has no attribute 'myFunction'
|
And ? Where is the name myFunction bound in the above code ?
| Quote: | but if I try to access the constants class:
from network_utils import constants
constants.NO_DATA_TYPE
'none'
it works, how come?
|
I suppose NO_DATA_TYPE is defined somewhere in one of your constants.py
files.
Instead of messing with eval and builtins and wonder why something
"works" and why something else doesn't, I strongly suggest you (re)read
the part about imports, packages, modules etc in the FineManual. |
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