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+--- Thread: is this a bug or not with if...else...? (/thread-12607.html)
is this a bug or not with if...else...? - meokey - Sep-02-2018
platform.python_version()'3.5.1'
a=None; b='abc'; c = b if a == None else a + ' & ' + bTraceback (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.
RE: is this a bug or not with if...else...? - Gribouillis - Sep-02-2018
If I copy and paste the same line of code in my python 3.5.2 interpreter, there is no error...
RE: is this a bug or not with if...else...? - Larz60+ - Sep-02-2018
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
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 syntaxRE: is this a bug or not with if...else...? - Gribouillis - Sep-03-2018
@Larz60+ You forgot a
+ in the reversed version, and you cannot inverse the assignment statement. The reversed version isa=None; b='abc'; c = a + ' & ' + b if a != None else band it also works.
RE: is this a bug or not with if...else...? - volcano63 - Sep-03-2018
Accepted (and more efficient) form of
None value check is is/is notif a is None: ..... if b is not None: .....