CODEWITHSUNDEEP
djangodjango-modelsdjango-views
Prakash Kumar
Prakash Kumar

Reputation: 2594

Apply Multi attribute search in Django

I am trying to implement Search in my list view for multiple attributes. I don't want to use multiple if-else for each attribute.

Here is my current code for search in list view:

def get_queryset(self):
    city = self.request.GET.get('city_name') or ''
    user = self.request.GET.get('user_name') or ''
    if (city != '' or user!=''):
        userqueries = user.split() 
        cityqueries = city.split() 
        if len(userqueries) and len(cityqueries):
            qset1 =  functools.reduce(operator.__or__, [
                Q(first_name__icontains=query) | Q(last_name__icontains=query) for query in userqueries])
            qset2 =  functools.reduce(operator.__or__, [Q(city__name__icontains=query)  for query in cityqueries])
            object_list = self.model.objects.filter(qset1 , qset2)
        elif len(userqueries):
            qset1 =  functools.reduce(operator.__or__, [
                Q(first_name__icontains=query) | Q(last_name__icontains=query) for query in userqueries])
            object_list = self.model.objects.filter(qset1)
        elif len(cityqueries):
            qset1 =  functools.reduce(operator.__or__, [Q(city__name__icontains=query)  for query in cityqueries])

            object_list = self.model.objects.filter(qset1)
    else:
        object_list = self.model.objects.all()
    return object_list

If I will add one attribute:

    city = self.request.GET.get('city_name') or ''
    user = self.request.GET.get('user_name') or ''
    state = self.request.GET.get('state_name') or ''

    if (city != '' or user!='' or state!=''):
        userqueries = user.split() 
        cityqueries = city.split() 
        statequeries = state.split() 
        if len(userqueries) and len(cityqueries):
            qset1 =  functools.reduce(operator.__or__, [
                Q(first_name__icontains=query) | Q(last_name__icontains=query) for query in userqueries])
            qset2 =  functools.reduce(operator.__or__, [Q(city__name__icontains=query)  for query in cityqueries])
            object_list = self.model.objects.filter(qset1 , qset2)
        elif len(userqueries) and len(statequeries):
            qset1 =  functools.reduce(operator.__or__, [
                Q(first_name__icontains=query) | Q(last_name__icontains=query) for query in userqueries])
            qset2 =  functools.reduce(operator.__or__, [Q(city__state__name__icontains=query)  for query in statequeries])
            object_list = self.model.objects.filter(qset1 , qset2)
        elif len(userqueries):
            qset1 =  functools.reduce(operator.__or__, [
                Q(first_name__icontains=query) | Q(last_name__icontains=query) for query in userqueries])
            object_list = self.model.objects.filter(qset1)
        elif len(cityqueries):
            qset1 =  functools.reduce(operator.__or__, [Q(city__name__icontains=query)  for query in cityqueries])
            object_list = self.model.objects.filter(qset1)
        elif len(statequeries):
            qset1 =  functools.reduce(operator.__or__, [Q(city__state__name__icontains=query)  for query in statequeries])
            object_list = self.model.objects.filter(qset1)

I want to merge all these condition in one:

        if len(userqueries) and len(cityqueries):

        elif len(userqueries):

        elif len(cityqueries):

Upvotes: 2

Views: 162

Answers (1)

willeM_ Van Onsem
willeM_ Van Onsem

Reputation: 477824

We probably better make a helper function that constructs a Q object that is the disjunction of several elements, like:

from django.db.models import Q
from functools import reduce
from operator import or_

def q_or_otherwise_true(iterable, *keys):
    iterable = list(iterable)
    if iterable:
        return reduce(or_, [Q(**{key: val}) for val in iterable for key in keys])
    else:
        return Q()

This thus generates Q objects like:

>>> q_or_otherwise_true(['foo'], 'col1__icontains', 'col2__icontains')
<Q: (OR: ('col1__icontains', 'foo'), ('col2__icontains', 'foo'))>
>>> q_or_otherwise_true(['foo', 'bar'], 'col1__icontains', 'col2__icontains')
<Q: (OR: ('col1__icontains', 'foo'), ('col2__icontains', 'foo'), ('col1__icontains', 'bar'), ('col2__icontains', 'bar'))>
>>> q_or_otherwise_true([], 'col1__icontains', 'col2__icontains')
<Q: (AND: )>

then we can generate this like:

def get_queryset(self):
    city = self.request.GET.get('city_name') or ''
    user = self.request.GET.get('user_name') or ''
    userqueries = user.split() 
    cityqueries = city.split()
    return self.model.objects.filter(
        q_or_otherwise_true(userqueries, 'first_name__icontains', 'last_name__icontains'),
        q_or_otherwise_true(cityqueries, 'city__name__icontains'),
    )

This works because or q_or_otherwise_true makes a disjunction of elements, given the iterable contains any elements. If not it constructs a Q() object, which - in a .filter(..) call - does not filter out anything. So that means we can thus make a conjucntion of these two.

The function can easily be extended to more calls, by simply making an extra q_or_otherwise_true call.

Upvotes: 1

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