is this a bug or not with if...else...?

[meokey]

1	platform.python_version()

'3.5.1'

1	a=None; b='abc'; c = b if a == None else a + ' & ' + b

Traceback (most recent call last):
File "<stdin>", line 1, in <module>
TypeError: unsupported operand type(s) for +: 'NoneType' and 'str'


I thought that the rest part after 'else' would not be interpreted since a==None.

Any thought please? Thank you.

[Gribouillis]

If I copy and paste the same line of code in my python 3.5.2 interpreter, there is no error...

[Larz60+]

looks like it violates PEP 20, but runs.
I don't see where the else is being interpreted as the 1st condition is satisfied.
reversed will give syntax error, because forced to run else code of first statement

1	a=None; b='abc'; a + ' & ' b if a != None else c = b

Output:
    a=None; b='abc'; a + ' & ' b if a != None else c = b
                               ^
SyntaxError: invalid syntax

[Gribouillis]

@Larz60+ You forgot a + in the reversed version, and you cannot inverse the assignment statement. The reversed version is

1	a=None; b='abc'; c = a + ' & ' + b if a != None else b

and it also works.

[volcano63]

Accepted (and more efficient) form of None value check is is/is not

1 2 3 4

if a is None: ..... if b is not None: .....