I have two functions:
def f(a,b,c=g(b)):
blabla
def g(n):
blabla
c
is an optional argument in function f
. If the user does not specify its value, the program should compute g(b) and that would be the value of c
. But the code does not compile - it says name 'b' is not defined. How to fix that?
Someone suggested:
def g(b):
blabla
def f(a,b,c=None):
if c is None:
c = g(b)
blabla
But this doesn't work. Maybe the user intended c
to be None and then c
will have another value.
def f(a,b,c=None):
if c is None:
c = g(b)
If None
can be a valid value for c
then you do this:
sentinel = object()
def f(a,b,c=sentinel):
if c is sentinel:
c = g(b)