python - django 聚合后的结果是什么？

Question

我在 django 项目中看到以下代码。我理解它是聚合，但是聚合后的 ['kw__sum'] 是什么？

Project.objects.filter(project = project).aggregate(Sum('kw'))['kw__sum']

谢谢

Answer 1

如果你查看 examples 就在这里你会看到aggregate返回字典，所以最后一部分只是字典查找

aggregation = Project.objects.filter(project = project).aggregate(Sum('kw'))
result = aggregation['kw__sum']

来自文档

Returns a dictionary of aggregate values (averages, sums, etc.) calculated over the QuerySet. Each argument to aggregate() specifies a value that will be included in the dictionary that is returned.