在 Django 中,如何使用动态字段查找过滤 QuerySet? [英] In Django, how does one filter a QuerySet with dynamic field lookups?
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问题描述
给定一个类:
from django.db import models
class Person(models.Model):
name = models.CharField(max_length=20)
是否有可能,如果有的话,如何拥有一个基于动态参数过滤的 QuerySet?例如:
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`.
推荐答案
Python 的参数扩展可以用来解决这个问题:
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)
这是一个非常常见且有用的 Python 习语.
This is a very common and useful Python idiom.
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