问题
Is it possible to define a function argument's default value to another argument in the same function definition? Something like:
def func(a, b=a):
print a, b
but that didn't work.
回答1:
No. This is not possible. The Python interpreter thinks that you want to assign the default value of argument b to a global variable a when there isn't a global variable a.
You might want to try something like this:
def func(a, b=None):
if b is None:
b = a
来源：https://stackoverflow.com/questions/33527745/function-arguments-default-value-equal-to-another-argument