How to swap values in a list with a conditional statement?

I would like to swap values in a list, and I haven’t been able to find exactly how to create a conditional swap, where if one value equals say 270 I would like to swap it for 90, but if the value is the reverse ie it equals 90 I would like to swap it for 270, the code, I believe involves an if-condition then, and an elseif-condition then, but I have been able to find how to create it.
Any help here will be appreciated. In the sample the other values remain unchanged, ie 0, 180 do not change.


You can use nested if statements within an if statement.

In the picture, in the if?true:false;, you can put another if statement in the false section. Here I put a==90?270:a into the false.



Thankyou Kenny,

Your help has solved a lot of pain for me, so elegant and so simple. I truly appreciate your quick response.