我的python函数不会返回或更新值

def getMove(win,playerX,playerY):

    #Define variables.
    movePos = 75
    moveNeg = -75
    running = 1

    #Run while loop constantly to update mouse's coordinates.
    while(running):

        mouseCoord = win.getMouse()
        mouseX = mouseCoord.getX()
        mouseY = mouseCoord.getY()
        print "Mouse X = ", mouseX
        print "Mouse Y = ", mouseY

        if mouseX >= playerX:
            playerX = movePos + playerX
            running = 0
        elif mouseX <= playerX:
            playerX = moveNeg + playerX           
            running = 0
        elif mouseY >= playerY:
            playerY = movePos + playerY            
            running = 0
        elif mouseY <= playerY:
            playerY = moveNeg + playerY            
            running = 0
    return playerX,playerY

def main():

    #Create game window.
    win = GraphWin("Python Game", 500, 500)
    drawBoard(win)

    #Define variables.
    playerX = 75
    playerY = 125
    keyX = 325
    keyY = 375
    running = 1


    #Create Key and Player objects, draw the key, but don't draw the player yet.
    key = Text(Point(keyX,keyY),"KEY")
    key.draw(win)

    while(running):
        print "player X = ", playerX
        print "Player Y = ", playerY
        drawBoard(win)
        getMove(win,playerX,playerY)
        player = Circle(Point(playerX,playerY),22)
        player.setFill('yellow')
        player.draw(win)
main()

我正在使用图形库来创建游戏.我的播放器和钥匙绘制在正确的位置.但是,当调用getMove函数时,我的playerX和playerY不会更新.我添加了调试打印语句以在运行游戏时查找其值,并且始终为75和125.

解决方法:

在python中,整数是不可变的-当您为变量分配新的整数值时,您只是使变量指向新的整数,而不更改其指向的旧整数值.

(列表是python中可变对象的一个​​示例,您可以对其进行修改,并且指向该列表的所有变量都将注意到更改-因为LIST已更改.)

同样,当您将变量传递给python中的方法,然后更改该方法中该变量指向的内容时,由于该变量是新变量,因此您也无需更改该变量指向该方法之外的内容.

要解决此问题,请将返回的playerX,playerY分配给方法之外的变量：

playerX,playerY = getMove(win,playerX,playerY)

标签：python,function,return,return-value
来源： https://codeday.me/bug/20191011/1893112.html