How to check if a value is None and save to another variable only if it is not None in Python-CodePudding

The following piece of code works fine.

a = 2.0
b = int(a)

And b is 2.

But the following does not work:

a = None
b = int(a)

I get the following error:

TypeError: int() argument must be a string, a bytes-like object or a real number, not 'NoneType'

This works:

a = None
if a != None:
    b = int(a)
else:
    b = 0

But it is too much code because I have several such variables in my use case that can be None.

What I want:

b = a, if a is not None.
b = 0, if a is None

Is there an elegant way of doing this with a built in function or something that I am not aware of the existence of...?

CodePudding user response：

If you need to try this a bunch of times, you could make a very small function with a try:...except:... block.

def try_int(v):
    try:
        return int(v)
    except TypeError:
        return 0

a = 2
b = try_int(a) # should return 2
c = None
d = try_int(c) # should return 0

This solution sticks to the principal of 'asking for forgiveness, not permission' and also not repeating yourself by having a bunch of separate try:...except:... blocks and instead just the one.

CodePudding user response：

Just a short way: b = int(a or 0)