python how to "negate" value : if true return false, if false return true

Question

if myval == 0:    nyval=1 if myval == 1:    nyval=0 

Is there a better way to do a toggle in python, like a nyvalue = not myval ?

Answer 1

Use the not boolean operator:

nyval = not myval 

not returns a boolean value (True or False):

>>> not 1 False >>> not 0 True 

If you must have an integer, cast it back:

nyval = int(not myval) 

However, the python bool type is a subclass of int, so this may not be needed:

>>> int(not 0) 1 >>> int(not 1) 0 >>> not 0 == 1 True >>> not 1 == 0 True 

Answer 2

In python, not is a boolean operator which gets the opposite of a value:

>>> myval = 0 >>> nyvalue = not myval >>> nyvalue True >>> myval = 1 >>> nyvalue = not myval >>> nyvalue False 

And True == 1 and False == 0 (if you need to convert it to an integer, you can use int())