Alan Isaac wrote:
I have a class `X` where many parameters are set
at instance initialization. The parameter values
of an instance `x` generally remain unchanged,
'Parameters' are the function local names in the header that get bound
to argument objects when the function is called. What you are
describing are 'attributes'.
but is there way to communicate to a method that
it depends only on the initial values of these parameters
(and does not need to worry about any changes)?
In the terms stated, no.
The behavior of method `m` depends on these parameter values.
It turns out `m` gets called a lot, which means
that the pameter values are accessed over and over
(self.p0, self.p1, etc). I would like to
manufacture a function equivalent to the method
that simply uses fixed values (the values at the
time it is manufactured).
You are now describing a function closure. Here is an example that
might help.
def f_maker(a1, a2):
def _(b): return a1*b + a2
return _
class C:
def __init__(self, attr1, attr2):
self.attr1 = attr1
self.attr2 = attr2
self.f = f_maker(attr1, attr2)
c = C(2,3)
print(*(c.f(i) for i in range(5)))
# 3 5 7 9 11
Having f use both initial and 'current' attribute values would be a bit
trickier ;-)
Terry Jan Reedy
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