如何根据 function 输入进行 django 查询？

Question

我想根据 function 输入进行 django 查询。我不想在 2 个单独的行中使用 if 和 else 检查输入，然后进行如下查询：

def customer_number(mall,store=None):
    if store :
        customer = models.Customer.objects.filter(mall=mall,store=store)
    else :
        customer = models.Customer.objects.filter(mall=mall)
    return customer.count

Answer 1

您可以构造一个查找 kwarg 字典：

def customer_number(mall, store=None):
    lookup_kwargs = {'mail': mail}
    if store:
        lookup_kwargs['store'] = store
    return models.Customer.objects.filter(**lookup_kwargs).count()

或者，如果您不想要任何条件，您可以构造dict并删除None值：

def customer_number(mall, store=None):
    lookup_kwargs = {'mail': mail, 'store': store}
    lookup_kwargs = {k: v for k, v in lookup_kwargs.items() if v is not None}
    return models.Customer.objects.filter(**lookup_kwargs).count()