Python Forum

In Python, anytime a variable is referenced, it will be looked for in the local scope, then enclosing scope, up to global. Methods are no different than functions in this way.

(Feb-19-2017, 04:37 AM)micseydel Wrote: [ -> ]In Python, anytime a variable is referenced, it will be looked for in the local scope, then enclosing scope, up to global. Methods are no different than functions in this way.

but if you want to assign a new value to a variable ...

interesting that self.foo = 1 can create a new attribute in a class instance but setattr() is needed in other cases.

(Feb-26-2017, 03:28 AM)Skaperen Wrote: [ -> ]interesting that self.foo = 1 can create a new attribute in a class instance but setattr() is needed in other cases.

What do you mean?

self.foo = 1
and
setattr(self, foo, 1)
would yield the same result

(Feb-26-2017, 09:49 AM)buran Wrote: [ -> ]

(Feb-26-2017, 03:28 AM)Skaperen Wrote: [ -> ]interesting that self.foo = 1 can create a new attribute in a class instance but setattr() is needed in other cases.

What do you mean?

self.foo = 1
and
setattr(self, foo, 1)
would yield the same result

you cannot add a new attribute using the first form, except for methods.

(Mar-02-2017, 04:29 AM)Skaperen Wrote: [ -> ]you cannot add a new attribute using the first form, except for methods.

What are you going on about?

>>> class Blank:
...     pass
...
>>> a = Blank()
>>> a
<__main__.Blank instance at 0x02B12760>
>>> a.foo
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
AttributeError: Blank instance has no attribute 'foo'
>>> a.foo = 5
>>> a.foo
5
>>>

(Feb-26-2017, 09:49 AM)buran Wrote: [ -> ]setattr(self, foo, 1)

just noticed the stupid accidental mistake. of course it should be setattr(self, 'foo', 1)

forum_import.py:

EGG = 'eggses'

class Egg(object):

    def __init__(self, style):
        self.style = style

egg = Egg('scrambled')
egg.scrapple = 'bacon'

forum_test.py:

from forum_import import *

HAM = 'hocks'

class Spam(object):

    def __init__(self, spice):
        self.spice = spice

    def test(self):
        print(self.spice)
        if hasattr(self, 'ham'):
            print(self.ham)
        print(HAM)
        print(EGG)
        print(egg.style)
        print(egg.scrapple)

spam = Spam('garlic')
spam.ham = 'Wilbur'
spam.test()

The output of running forum_test.py:

garlic
Wilbur
hocks
eggses
scrambled
bacon

Correct me if I'm wrong, but doesn't this cover everything you're talking about? If you are defining something like HAM, and your Spam instance can't see it, there is some other problem going on. It's not a namespace issue.