[英]hybrid_property raises a TypeError in if/else
I'd like to do some formatting on the id in a hybrid property so that numbers under 10 are prefixed with a P0 (P01, P02, 03, etc). 我想对混合属性中的id进行一些格式化,以便10以下的数字以P0为前缀(P01,P02、03等)。 The following code is throwing a
TypeError: Boolean value of this clause is not defined
from the __bool__
method in elements.py. 以下代码
TypeError: Boolean value of this clause is not defined
从__bool__
中的__bool__
方法TypeError: Boolean value of this clause is not defined
。 What am I missing? 我想念什么?
In my models.py: 在我的models.py中:
@hybrid_property
def conversion_number(self):
return 'P0{}'.format(self.id) if self.id < 10 else 'P{}'.format(self.id)
This was my fix: 这是我的解决办法:
@property
def conversion_number(self):
return 'P0{}'.format(self.id) if self.id < 10 else 'P{}'.format(self.id)
The issue seemed to be that id is an InstrumentedAttribute (not an int) when sqlalchemy is initializing the model. 问题似乎是当sqlalchemy初始化模型时,id是InstrumentedAttribute(不是int)。 This behavior is strange because my implementation isn't substantially different from the example in the SQLAlchemy docs.
这种行为很奇怪,因为我的实现与SQLAlchemy文档中的示例没有太大不同。
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