Question

尝试让groupby过滤器正常工作我收到Atribute错误。我的groupby代码如下：

{% for year, year_purchases in purchases|groupby('PurchaseDate.year')|reverse %}
            <h2 class="year">{{ year }}</h2>
            {% for ... %}
            {% endfor %}
{% endfor %}

购买是PurchaseEntity的列表：

class PurchaseEntity:
    def __init__(self):
        self.PurchaseDate = ''
        self.Orders = []

    def load_from_query(self,result):
        self.PurchaseDate = result.PurchaseDate

我收到以下错误：

AttributeError
AttributeError: PurchaseEntity instance has no attribute '__getitem__'

问题似乎在environment.py：

def getitem(self, obj, argument):
"""Get an item or attribute of an object but prefer the item."""
try:
    return obj[argument]
except (TypeError, LookupError): #<-- Here it raises the error
    if isinstance(argument, basestring): #<-- It never reaches here
        try:
            attr = str(argument)
        except Exception:
            pass
        else:
            try:
                return getattr(obj, attr)
            except AttributeError:
                pass
    return self.undefined(obj=obj, name=argument)

我不认为它是Jinja2或＆＃34; groupby＆＃34;错误，因为getitem函数无处不在。我用谷歌搜索它并且无法解决任何相关问题。但是，我所做的是更改＆＃34;除了（TypeError，LookupError）：＆＃34; line和它适用于任何这些替代方案：

except:
except Exception:

我不知道我的课程演示是否错误，或者我是否只是遗漏了某些内容，因为我尝试了其他作品（由SQLAlchemy创建并使用自动加载）并且工作正常。有什么建议吗？

顺便说一下，发送给getitem的参数是：

>>> (obj,argument)
(<project.logic.purchase.PurchaseEntity instance at 0x050DF148>, 'PurchaseDate')
>>> obj.PurchaseDate
datetime.datetime(2012, 9, 25, 17, 1, 44)

Answer 1

尝试制作PurchaseEntity扩展对象：

class PurchaseEntity(object):

当您尝试查找项目并且没有它时，不扩展任何内容的基本类会抛出AttributeError。对象抛出TypeError。

>>> class Foo:
...     def foo(self):
...             void    
... 
>>> class Bar(object):
...     def bar(self):
...             void
... 
>>> foo = Foo()
>>> bar = Bar()
>>> foo['foo']
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
AttributeError: Foo instance has no attribute '__getitem__'
>>> bar['bar']
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: 'Bar' object has no attribute '__getitem__'

使用Jinja2 grouby过滤器的属性错误

1 个答案: