problem with Python class creating

[dmitrey]

Hi all,
I have the code like this one:

from myMisc import ooIter
class MyClass:
def __init__(self): pass
iterfcn = lambda *args: ooIter(self) # i.e pass the class instance
to other func named ooIter
field2 = val2
field3 = val3 # etc

So it yields "global name 'self' is not defined", that is true. How
could I handle the situation?

Currently I do (and it works, but give me some troubles - I should
call MyClass.__init__ for each children class, and there are lots of
those ones)

class MyClass:
def __init__(self):
iterfcn = lambda *args: ooIter(self) # i.e pass the class
instance to other func named ooIter
field2 = val2
field3 = val3 # etc

I suspect it has better solution, is it?
Thank you in advance, Dmitrey

 

[Bruno Desthuilliers]

dmitrey a écrit :

Hi all,
I have the code like this one:

from myMisc import ooIter
class MyClass:

Unless you have a need for compatibility with aged Python versions,
you'd be better using new-style classes:

class MyClass(object):

def __init__(self): pass

This is the default behaviour, so you may as well get rid of this line.

iterfcn = lambda *args: ooIter(self) # i.e pass the class instance
to other func named ooIter

cf below about this...

field2 = val2
field3 = val3 # etc

You're aware that these two attributes are *class* attributes (that is,
shared by all instances) ?

So it yields "global name 'self' is not defined", that is true.
Indeed.

How
could I handle the situation?

iterfcn = lambda self: ooIter(self)

which could as well be written:

def iterfcn(self):
ooIter(self)


Remember that Python's methods are - at least at this stage - plain
functions, so the 'self' parameter is *not* optional - else how could
the function access the current instance ?

And FWIW, you don't need the *args if you don't use any other than 'self'.

Currently I do (and it works, but give me some troubles - I should
call MyClass.__init__ for each children class,

Not unless these classes define their own initializers. But that's
another problem

and there are lots of
those ones)

class MyClass:
def __init__(self):
iterfcn = lambda *args: ooIter(self)

The real problem is that you create one anonymous function *per instance*.

I suspect it has better solution, is it?

Indeed.

 

[timaranz]

Hi all,
I have the code like this one:

from myMisc import ooIter
class MyClass:
def __init__(self): pass
iterfcn = lambda *args: ooIter(self) # i.e pass the class instance
to other func named ooIter
field2 = val2
field3 = val3 # etc

So it yields "global name 'self' is not defined", that is true. How
could I handle the situation?

Currently I do (and it works, but give me some troubles - I should
call MyClass.__init__ for each children class, and there are lots of
those ones)

class MyClass:
def __init__(self):
iterfcn = lambda *args: ooIter(self) # i.e pass the class
instance to other func named ooIter
field2 = val2
field3 = val3 # etc

I suspect it has better solution, is it?
Thank you in advance, Dmitrey

without having tested - I think this should work for you:

from myMisc import ooIter

class MyClass:
def __init__(self): pass
iterfcn = lambda self: ooIter(self)

 

[dmitrey]

Thanks all for these detailed explanations.

dmitrey a écrit :
Not unless these classes define their own initializers. But that's
another problem



The real problem is that you create one anonymous function *per instance*.

No, it's not a problem - it's desired behaviour.
Regards, Dmitrey