# Ternary operator behavior

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Category：Languages

I recently started using ternary operator but I encountered a case where I needed to use multiple ternary operator in the same line, but they didn't seem to work as I expected.

Can someone please give a explanation why those line give different result.

``x = 1 if True else 2 + 3 if False else 4  # x = 1, I expected 5 x = (1 if True else 2) + (3 if False else 4)  # x = 5 ``

If I add parentheses I get the expected result, but I don't understand what the parentheses change.

And if I rotated the addition, without the parentheses, I get the correct value.

``3 if False else 4 + 1 if True else 2  # x = 5 ``

However, I get wrong result if the second ternary operator is False:

``3 if False else 4 + 1 if False else 2  # x = 5 # x = 2 ??? ``

Is it because you shouldn't multiple ternary operator in the same line, or is their an other reason?

Think of it as applying parentheses around each of the three inputs:

``x = (1) if (True) else ((2 + 3) if (False) else (4)) ``

Here you can clearly see that `x` will equal `1` and that your `2 + 3...` won't be run.

When you 'rotated' it:

``(3) if (False) else ((4 + 1) if (True) else (2)) ``

So now the `3` doesn't run because the condition is `False` so you get the `4 +...` term instead

``(3) if (False) else ((4 + 1) if (False) else (2)) ``
it returns `2` because the `(4+1)` is the true condition for your second condition (which is `False`)
If you're still confused, write it out as a regular `if` statement:
``x = (1) if (True) else ((2 + 3) if (False) else (4)) ``
``if True:     x = 1 else:     if False:         x = 2 + 3     else:         x = 4 ``