Hello
If I have the Vector class below, is there a means by which I can have
the following behaviour A = Vector(1, 2)
print A
(1, 2)A = 0
print A
(0, 0)
If there is such a means, will it still work with the __slots__
attribution uncommented?
Thanks
class Vector(object):
#__slots__ = ('x', 'y')
def __init__(self, a=0, b=0 ):
self.x = a
self.y = b
def __repr__(self):
return '(%s, %s)' % (self.x, self.y) 6  1382 
Gerard Flanagan wrote: Hello
If I have the Vector class below, is there a means by which I can have
the following behaviour
A = Vector(1, 2)
print A
(1, 2)
A = 0
print A
(0, 0)
If there is such a means, will it still work with the __slots__
attribution uncommented?
No, you can't. The reason is that python doesn't have an assignment
operator as e.g. C++ has. The "=" just binds the name A to some object -
without the object knowing it.
What's wrong with
class A:
def clear():
pass
...
A.clear()
? Alternatively, you could try and abuse one of the seldom used in-place
operator like __ior__:
A |= 0
But I wouldn't recommend that.
Regards,
Diez
Gerard Flanagan wrote: Hello
If I have the Vector class below, is there a means by which I can have
the following behaviour
A = Vector(1, 2)
print A
(1, 2)
A = 0
print A
(0, 0)
If there is such a means, will it still work with the __slots__
attribution uncommented?
No, you can't. The reason is that python doesn't have an assignment
operator as e.g. C++ has. The "=" just binds the name A to some object -
without the object knowing it.
What's wrong with
class A:
def clear():
pass
...
A.clear()
? Alternatively, you could try and abuse one of the seldom used in-place
operator like __ior__:
A |= 0
But I wouldn't recommend that.
Regards,
Diez
Gerard Flanagan wrote: If I have the Vector class below, is there a means by which I can have
the following behaviour
A = Vector(1, 2)
print A (1, 2)
A = 0
that operation rebinds A; it doesn't affect the Vector instance in any way.
more here: http://effbot.org/zone/python-objects.htm
</F>
Gerard Flanagan wrote: If I have the Vector class below, is there a means by which I can have
the following behaviour
A = Vector(1, 2)
print A (1, 2)
A = 0
that operation rebinds A; it doesn't affect the Vector instance in any way.
more here: http://effbot.org/zone/python-objects.htm
</F>
On 19 Nov 2005 05:29:07 -0800
"Gerard Flanagan" <gr********@yahoo.co.uk> wrote: If I have the Vector class below, is there a means by
which I can have the following behaviour
A = Vector(1, 2)
print A (1, 2)A = 0
print A
(0, 0)
As has already been mentioned, "A = 0" rebinds the name "A"
to the object "0" so there's no way it can mutate the object
A.
However, you could create an object "Origin" to use as a
vector zero:
Origin = Vector(0,0)
Or if you want to be shorter, more poetic, and make future
maintainers curse you, you can call it "O":
O = Vector(0,0)
;-)
--
Terry Hancock (ha*****@AnansiSpaceworks.com)
Anansi Spaceworks http://www.AnansiSpaceworks.com
On 19 Nov 2005 05:29:07 -0800
"Gerard Flanagan" <gr********@yahoo.co.uk> wrote: If I have the Vector class below, is there a means by
which I can have the following behaviour
A = Vector(1, 2)
print A (1, 2)A = 0
print A
(0, 0)
As has already been mentioned, "A = 0" rebinds the name "A"
to the object "0" so there's no way it can mutate the object
A.
However, you could create an object "Origin" to use as a
vector zero:
Origin = Vector(0,0)
Or if you want to be shorter, more poetic, and make future
maintainers curse you, you can call it "O":
O = Vector(0,0)
;-)
--
Terry Hancock (ha*****@AnansiSpaceworks.com)
Anansi Spaceworks http://www.AnansiSpaceworks.com This thread has been closed and replies have been disabled. Please start a new discussion. Similar topics
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Hello
If I have the Vector class below, is there a means by which I can have
the following behaviour
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