All,
Another one, this time a bit shorter.
It looks like defaults for arguments are only bound once, and every
subsequent call reuses the first reference created. Hence the
following will print '[10,2]' instead of the expected '[1,2]'.
Now my question - exactly why is 'default_me()' only called once, on
the construction of the first object? And what's the best way to get
around this if you want to have a default for an argument which so
happens to be a reference or a new object?
---- code begins here ---
import copy
class A:
def default_me():
return [1,2]
def __init__(self, _arg=default_me()):
self.arg = _a
a = A()
a.arg[0] = 10
b = A()
print b.arg # prints [10,2]
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