从django.db导入模型
class Person(models。模型):
name = models.CharField(max_length = 20)
如果是这样,要有一个基于动态参数过滤的QuerySet?例如:
#而不是:
Person.objects.filter(name__startswith ='B')
#...和:
Person.objects.filter(name__endswith ='B')
#...有一些方法,给出:
filter_by ='{ 0} __ {1}'。格式('name','startswith')
filter_value ='B'
#...你可以运行相当于此?
Person.objects.filter(filter_by = filter_value)
#...将抛出异常,因为`filter_by`不是
#一个Person属性。
帮助非常感激和欣赏谢谢你提前。
解决方案Python的参数扩展可能用于解决这个问题:
kwargs = {
'{0} __ {1}'。format('name','startswith'):'A',
'{0} __ {1}'。format('name','endswith'):'Z'
}
Person.objects.filter(** kwargs)
这是一个非常常见和有用的Python成语。
Given a class:
from django.db import models
class Person(models.Model):
name = models.CharField(max_length=20)
Is it possible, and if so how, to have a QuerySet that filters based on dynamic arguments? For example:
# Instead of:
Person.objects.filter(name__startswith='B')
# ... and:
Person.objects.filter(name__endswith='B')
# ... is there some way, given:
filter_by = '{0}__{1}'.format('name', 'startswith')
filter_value = 'B'
# ... that you can run the equivalent of this?
Person.objects.filter(filter_by=filter_value)
# ... which will throw an exception, since `filter_by` is not
# an attribute of `Person`.
Help is much appreciated & thank you in advance.
解决方案Python's argument expansion may be used to solve this problem:
kwargs = {
'{0}__{1}'.format('name', 'startswith'): 'A',
'{0}__{1}'.format('name', 'endswith'): 'Z'
}
Person.objects.filter(**kwargs)
This is a very common and useful Python idiom.
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