局部变量'delete'全局变量赋值前引用

Question

我在项目开始时设置了一个全局变量delete，就在导入的库的正下方和任何类之前，但是当我有这段代码时:

def motion_notify_callback(event):
        if (ispymol == True):
            if event.inaxes is ax:      
            x = event.xdata
            y = event.ydata
            x = round(x,0)
            y = round(y,0)
            x = int(x)
            y = int(y)
            coord = (x,y)

            for i in range(0,len(number_list)):
                if (coord == number_list[i]):
                if (delete == True):
                    pymol.cmd.do("delete CurrentCont")
                    delete = False
                pymol.cmd.do("distance CurrentCont, chain"+lc+" and resi "+resi1[i]+" and name CA, chain"+lc+" and resi "+resi2[i]+" and name CA")
                    delete = True
            for i in range(0,len(rres)):
            if (coord == mappingpredcont[i]):
               if (delete == True):
                       pymol.cmd.do("delete CurrentCont")
                       delete =False
               pymol.cmd.do("distance CurrentCont, chain"+lc+" and resi "+predresi1[i]+" and name CA, chain"+lc+" and resi "+predresi2[i]+" and name CA")
                   delete = True

在全局变量赋值之前引用了错误的局部变量'delete'我哪里做错了?

Answer 1

你需要告诉Python你打算给一个全局变量赋值:

def motion_notify_callback(event):
    global delete
    ...

Answer 2

您需要在函数开始时将delete定义为global:

def motion_notify_callback(event):
   global delete
   .....