django - 如何在 django admin 验证器中处理尚未创建的列表

Question

我创建了一些自定义管理员验证，就像我想要的一样，除了在一种情况下。

它旨在检查以确保在多对多字段中创建的列表具有正确数量的项目（“玩家”），并且列表中的男女比例是可以接受的。

def clean(self):
    super(GameRosterForm, self).clean()
    players = self.cleaned_data.get('players', None)
    RosterRulesOn = self.cleaned_data.get('RosterRulesOn', None)
    women = players.filter(sex='F')
    womenPct = int((women.count()/float(players.count()))*100)
    if RosterRulesOn is True and players.count() < 8:
        raise ValidationError('Rosters must have at least 8 players. You have only selected %s.' % (players.count())) 
    if RosterRulesOn is True and players.count() > 18:
        raise ValidationError('Rosters cannot have more than 18 players. You have selected %s.' % (players.count()))
    if RosterRulesOn is True and womenPct < 40:
        raise ValidationError('Women must make up at least 40 percent of roster. They only constitute %s percent now.' % (womenPct))   
    return self.cleaned_data

正如我所说，它在大多数情况下都可以正常工作，但是当用户尚未将播放器添加到 m2m 时，它会返回错误：'list' object has no attribute 'filter' with reference to the women=players.filter(性别='F') 行。

我尝试了一些“if”和“try”条件来尝试绕过问题，但找不到有效的解决方案。

Answer 1

这个怎么样：

players = self.cleaned_data.get('players', None)
RosterRulesOn = self.cleaned_data.get('RosterRulesOn', None)
women = [player for player in players if player.sex=='F']
womenPct = int((len(women)/float(players.count()))*100)