python如何“否定”值:如果为真返回假,如果为假返回真

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时间:2020-08-19 00:39:37  来源:igfitidea点击:

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

pythonbooleannegate

提问by user2239318

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 ?

有没有更好的方法在 python 中进行切换,比如 nyvalue = not myval ?

采纳答案by Martijn Pieters

Use the notboolean operator:

使用not布尔运算符

nyval = not myval

notreturns a booleanvalue (Trueor False):

not返回一个布尔值(TrueFalse):

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

If you must have an integer, cast it back:

如果您必须有一个整数,请将其转换回:

nyval = int(not myval)

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

但是,pythonbool类型是 的子类int,因此可能不需要:

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

回答by TerryA

In python, notis a boolean operator which gets the opposite of a value:

在python中,not是一个布尔运算符,它与值相反:

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

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

True == 1False == 0(如果你需要将其转换为整数,则可以使用int()

回答by Klaus Byskov Pedersen

Use not, for example:

使用not,例如:

return not myval