Python if not == vs if !=

Question

What is the difference between these two lines of code:

if not x == \'val\':

and

if x != \'val\':

Is one

Answer 1

An additional note, since the other answers answered your question mostly correctly, is that if a class only defines __eq__() and not __ne__(), then your COMPARE_OP (!=) will run __eq__() and negate it. At that time, your third option is likely to be a tiny bit more efficient, but should only be considered if you NEED the speed, since it's difficult to understand quickly.