Question

I am creating an app that basically stores shoe sizes, along with other information. I have been using the Django Decimal field to store the sizes, however the decimal field stores sizes like 10 as 10.0, so my question is, is there a way to make or if already exists a field that when provided an int ( 10 ) it stores the value as int and when provided a decimal ( 10.5 ) then stores it as decimal ?

Answer 1

TBH涉及一只鞋场,可能使用一个有选择的沙田——有效鞋子数量相对较少,因此,你可以如何安排他们。

如果它属于可能包含除鞋以外的东西的产品模式的一部分,那么规模的沙田就是有益的,因为你也可以储存M 、L 、XXL等值。

你不敢在鞋子上做任何算术,这样就没有点要使用 Dec。

出于这一原因,它实际上并不涉及 d中挽救的东西,只有你所显示的,而且......j_syk在评论中提出了与这些内容大致相同的好备选建议。

Answer 2

难道不简单地把它交给你细致的工作吗? 你可以把你储存起来,但在提交你的数据时,把数字安排到你所喜欢的身上。

>>> str(Decimal(10))
 10 
>>> str(Decimal(10.5))
 10.5 
>>> str(Decimal(10.0))
 10

Answer 3

我通过了这一解决办法:

Create a custom Django model Field
Which return a custom decimal.Decimal instance that implements the trick in __unicode__ because this is just a matter of representation

The snippet:

class PyPrettyDecimal(decimal.Decimal): 

    def __unicode__(self): 
        # TODO: to improve with decimal properties ?!? 
        mod = self - int(self) 
        if not mod: 
            rv = int(self) 
        else: 
            rv = self.quantize(mod.normalize()) 
        return unicode(rv) 

class PrettyDecimalField(models.DecimalField): 

    __metaclass__ = models.SubfieldBase 

    def to_python(self, value): 
        if value is None: 
            return value 
        try: 
            return PyPrettyDecimal(value) 
        except decimal.InvalidOperation: 
            raise exceptions.ValidationError(self.error_messages[ invalid ])

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