在Python的另一个函数中使用函数时，是否可以隐藏函数的某些返回值？

Question

I have a K function that returns three values (a,b and c) and I am using it in multiple places in my programme. I also want to use this function inside an H function. However, when I use it inside H function, I want it to return only its first two return values (a and b), just like in the code below. Is there a way with which I can hide the c when I use K inside H? Or should I just redefine K function inside H function separately in such a way that it returns only a and b values?

def K(x):
  ...
  return a,b,c

def H(y):
  ...
  a,b=K(y)
  ...
  return p

Thanks!

Answer 1

You can use underscore '_'

def foo():
  return 3,4,5

x,_,_ = foo()
print(x)

output

3

Answer 2

If the values you are returning are the first ones (eg only a, or only a and b), then your code will work as is.

If the values you are returning aren't the first ones (eg only b, or a and c), you'd need to use something like a, _, c = K(y) (the _ is the common sign of a "dummy" variable).

Answer 3

You can also add a type check in the Function K:

def K(x, return_only_ab=False): # add default parameter return_only_ab
  ...
  if not return_only_ab: # if False then return all the three variables
     return a,b,c
  else: # else reutrn only a, b that you need
     return a, b

def H(y):
  ...
  a,b=K(y, return_only_ab=True) # here you ll only get a,b and then do something with it
  ...
  return p

hope it helps