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I'm working with a query that looks like so:
filters = Q(is_default = False)
# Build the excludes and filters dynamically
if cut:
filters = filters & Q(mailbagstats__num_letters2__gt = int(cut) )
Given the filters Q query, can I pop one of the queries?
I'd like to remove the Q(mailbagstats__num_letters2__gt= int(cut) ) query from this Q query for a new filter down the line.
Normally, I use lists and reduce but this one is constructed via Q() & Q() so I'm not sure how to modify it.
Thanks for any input you might have!
592
Django gives you two ways of performing raw SQL queries: you can use Manager. raw() to perform raw queries and return model instances, or you can avoid the model layer entirely and execute custom SQL directly. Explore the ORM before using raw SQL!
Django Q is a native Django task queue, scheduler and worker application using Python multiprocessing.
pk is short for primary key, which is a unique identifier for each record in a database. Every Django model has a field which serves as its primary key, and whatever other name it has, it can also be referred to as "pk".
You can pop them:
>>> filter = Q(a=True)
>>> filter = filter & Q(b=True)
>>> filter.children
[('a', True), ('b', True)]
>>> filter.children.pop()
('b', True)
>>> filter.children
[('a', True)]
Why don't you work with lists and made the filter at the end?
filters = []
filters.append(Q(is_default = False))
# Build the excludes and filters dynamically
if cut:
filters.append(Q(mailbagstats__num_letters2__gt = int(cut)))
# I want to pop the last one
filters.pop()
# build the filter before making the query
# Note that this call will remove an element from the filters list
filters_for_query = reduce(lambda a, x: a & x, filters, filters.pop())
Model.objects.filter(filters_for_query)
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