Nik Nik - 9 months ago 15
Python Question

How to pass an empty parameter to a python function?

Here is the working code:

def g(y=10):
return y**2

def f(x,y=10):
return x*g(y)

print(f(5)) #->500

However, let's suppose we don't want to remember and copy a default value of keyword parameter
to the definition of external function (especially if there are several layers of external functions). In the above example it means that we want to use parameter, already defined in

One way to do that:

def f(x,y=None):
if y==None: return x*g()
else: return x*g(y)

But is there a cleaner way to do the same?
Something like:

def f(x,y=empty()):
return x*g(y)


Interesting question! Here's another possibility, however this requires handing in the second parameter as a named parameter.

>>> def g(y=10):
...     return y**2
>>> def f(x, **kwargs):
...     return x * g(**kwargs)
>>> f(5)
>>> f(5, y=0)