Python变量不会改变吗? [英] Python variable won't change?

问题描述

我正在用python制作游戏，并且我已经设置了一些代码:

I'm making a game in python, and I have some code set up as such:

istouching = False
death = True

def checkdead():
    if istouching:
        print "Is touching"     
        death = True

while death is False:
    print death
    game logic

我知道游戏逻辑在起作用，因为正在触摸"会打印出来，但是当我打印出死亡值时，它仍然是错误的，有什么帮助吗?

I know the game logic is working, because "Is touching" prints, but then when I print out the value of death, it remains false, any help?

推荐答案

使checkdead返回值:

def checkdead():
    if istouching:
        print "Is touching"     
        return True

death = checkdead()

您也可以使用global，如@AshwiniChaudhar所示，但我认为编写返回值的函数而不是修改全局变量的函数是可取的，因为这样的函数可以更容易地进行单元测试，并且可以显式地进行测试.哪些外部变量发生了变化.

You could also use global, as @AshwiniChaudhar shows, but I think it is preferable to write functions that return values instead of functions that modify globals, since such functions can be unit-tested more easily, and it makes explicit what external variables are changed.

PS. if istouching = True应该导致了SyntaxError，因为您不能在条件表达式中进行变量赋值.

PS. if istouching = True should have resulted in a SyntaxError since you can not make a variable assignment inside a conditional expression.

相反，使用

if istouching:

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