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Mike Brooks
3,389 PointsSetting argument = None causes no accumulation
From the Python tutorial I excerpted the following code:
def f(a, L=[]):
L.append(a)
return L
def f2(a, L=None):
if L is None:
L = []
L.append(a)
return L
print(f(1))
print(f(2))
print(f(3))
print(f2(1))
print(f2(2))
print(f2(3))
Which yields the following results:
[1]
[1, 2]
[1, 2, 3]
[1]
[2]
[3]
It was showing how in the case of function f(), the contents of the L list are accumulating with each call and how if you alternatively in f2() set L = None it does not.
Maybe this is just something I should take as True but what about setting L = None overrides the notion that the argument is only instantiated at function definition time.
Thanks,
