Python条件变量赋值

Question

Morning all,

Can someone advise, is it possible to achieve something like this:

def myFunction(someParam)
   if someParam == 1:
      return "This and that"
   else:
      return None

someVariable = someVariable || myFunction(valuePassedIn)

ie, given "someVariable" has an existing value, I want to preserve that value, or replace it with the value returned from "myFunction", provided that is not None?

Obviously, I can do something like:

if myFunction(valuePassedIn) != None:
    someVariable = myFunction(valuePassedIn)

But this of course is calling myFunction twice. Alternatively, I could do:

myFuncRes = myFunction(valuePassedIn)
if MyFuncRes != None:
    someVariable = myFuncRes

But it'd be good if I could reduce this to a single line of code, as per my "||" line in the first code snippet above. Obviously I've seen the conditional expressions documentation , but unless I'm misunderstanding, this would still involve calling myFunction twice?

I guess one other option would be to pass someVariable in as an additional param to myFunction and use this as the "else" return instead of None, but I can't help feeling this is kinda messy - and Python probably has something more slick I could use?

Thanks

Answer 1

Yes you can do this

Please check below code

>>> a = 1
>>> def test(b):
...     return b*10
...
>>> c = a or test(2)
>>> c
1
>>> a = 0
>>> c = a or test(2)
>>> c
20