Ternary Operator SyntaxError

Question

I am trying to practice using ternary operators and I want to use them to set a value to False or True, but I am getting an error. Do you guys know what I am doing wrong?

play = False if ans.lower() is 'n' else play = True

[related](https://stackoverflow.com/questions/4728073/what-is-the-difference-between-an-expression-and-a-statement-in-python) — hilberts_drinking_problem, Aug 12 '19 at 00:08
Although that's the same as `play = ans.lower() is 'n'`, so the ternary operator is of not much use here. — krisz, Aug 12 '19 at 00:31

paxdiablo · Answer 1 · 2019-08-12T00:38:44.227

You can fix your immediate problem with:

play = False if ans.lower() is 'n' else True

without the extra assignment after the else. The basic idea of the ternary is:

finalValue = valueOne if someCondition else valueTwo

However, there are other problems with that⁽¹⁾, so I'd suggest the more succinct:

play = (ans.lower() != 'n')

⁽¹⁾ Amongst them the fact that is checks for identity equality, not value equality. See, for example:

>>> x = 9999
>>> y = 9999
>>> x == y
True
>>> x is y
False

You'll notice that the two objects are distinct even though they have the same value.

Secondly, you don't actually need a ternary if you're using a boolean value to feed into it, you can just use the boolean operators to manipulate it.

Any ternary of the forms:

True if condition else False
False if condition else True

can be better espressed as (respectively):

condition
not condition

Ternary Operator SyntaxError

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