Question

我正在使用python来尝试模拟Inform 7的基本功能（inform7.com）。当我试图设置房间打印出其中的所有对象，并且房间中没有对象时，它仍打印出In this room there is a。代码的相关部分就在这里。

def __repr__(self):
    if self.room_firstrun:
        for i in things:
            if things[i] == self.name:
                self.objects_in_room.append(i)
        self.room_firstrun = False

    fullstring = 'In this room, there is a '
    for i in self.objects_in_room:
        if not self.objects_in_room:
            fullstring = ''
            break
        elif i == self.objects_in_room[len(self.objects_in_room) - 1] and len(self.objects_in_room) > 2:
            stringtoappend = ', and a ' + i + '.'
        elif i == self.objects_in_room[len(self.objects_in_room) - 1] and len(self.objects_in_room) == 2:
            stringtoappend = ' and a ' + i + '.'
        elif i == self.objects_in_room[len(self.objects_in_room) - 1] and len(self.objects_in_room) == 1:
            stringtoappend = i + '.'
        elif i == self.objects_in_room[0]:
            stringtoappend = i
        else:
            stringtoappend = ', a ' + i
    fullstring += stringtoappend
    stringtoappend = ''
    return '\n----------' + self.name + '----------\n\n' + self.desc + '\n\n' + fullstring

。即使我通过删除所有项目验证列表为空，也永远不会到达行if not self.objects_in_room: fullstring = '' break。我一直试图修复它一段时间，但它一直没有工作。同样烦人的是，当我在一个房间里有两件物品时，它没有显示第一件物品。也许我应该把它放在另一个问题上。在此先感谢您的回答！

Answer 1

从未到达

if not self.objects_in_room因为它位于for循环中，并且for循环仅在self.objects_in_room不为空时运行。要解决此问题，请将if not self.objects_in_room置于循环之外

def __repr__(self):
    if self.room_firstrun:
        for i in things:
            if things[i] == self.name:
                self.objects_in_room.append(i)
        self.room_firstrun = False

    fullstring = 'In this room, there is a '
    if not self.objects_in_room:
            fullstring = ''
    for i in self.objects_in_room:

        if i == self.objects_in_room[len(self.objects_in_room) - 1] and len(self.objects_in_room) > 2:
            fullstring += ', and a {0}.'.format(i)
        elif i == self.objects_in_room[len(self.objects_in_room) - 1] and len(self.objects_in_room) == 2:
            fullstring += ' and a {0}.'.format(i)
        elif i == self.objects_in_room[len(self.objects_in_room) - 1] and len(self.objects_in_room) == 1:
            fullstring += '{0}.'.format(i)
        elif i == self.objects_in_room[0]:
            fullstring += i
        else:
            fullstring += ', a {0}'.format(i)
    return '\n----------' + self.name + '----------\n\n' + self.desc + '\n\n' + fullstring

或者你可以这样做：如果你使用for..else语句使用python 3。

def __repr__(self):
    if self.room_firstrun:
        for i in things:
            if things[i] == self.name:
                self.objects_in_room.append(i)
        self.room_firstrun = False

    fullstring = 'In this room, there is a '

    for i in self.objects_in_room:

        if i == self.objects_in_room[len(self.objects_in_room) - 1] and len(self.objects_in_room) > 2:
            fullstring += ', and a {0}.'.format(i)
        elif i == self.objects_in_room[len(self.objects_in_room) - 1] and len(self.objects_in_room) == 2:
            fullstring += ' and a {0}.'.format(i)
        elif i == self.objects_in_room[len(self.objects_in_room) - 1] and len(self.objects_in_room) == 1:
            fullstring += '{0}.'.format(i)
        elif i == self.objects_in_room[0]:
            fullstring += i
        else:
            fullstring += ', a {0}'.format(i)
    else:
        fullstring = ''
    return '\n----------' + self.name + '----------\n\n' + self.desc + '\n\n' + fullstring

你为什么使用stringtoappend？为什么不直接将它添加到fullstring？

带有空列表

1 个答案: