Aim to Achieve:
I want all objects where name attribute contains any word from the list.
I have:
list = ['word1','word2','word3']
ob_list = data.objects.filter( // What to write here ? )
// or any other way to get the objects where any word in list is contained, in
// the na-me attribute of data.
For example:
if name="this is word2": Then object with such a name should be returned since word2 is in the list.
Please help!
You could use Q objects to constuct a query like this:
from django.db.models import Q
ob_list = data.objects.filter(reduce(lambda x, y: x | y, [Q(name__contains=word) for word in list]))
Edit:
reduce(lambda x, y: x | y, [Q(name__contains=word) for word in list]))
is a fancy way to write
Q(name__contains=list[0]) | Q(name__contains=list[1]) | ... | Q(name__contains=list[-1])
You could also use an explicit for loop to construct the Q object.
lambda is just a way of defining a function right there instead of defining it elsewhere, and reduce repeatedly applies an operation repeatedly on a list: reduce(lambda x, y: x+y, [1, 2, 3, 4, 5]) does ((((1+2)+3)+4)+5). The reduction by bitwise OR over the list of Qs is the same as the any over the list in my answer.
OR is performed at the database level instead of fetching all the records and filtering them in python.OR I meant the actual filtering (i.e. the WHERE clause has name LIKE ... OR name LIKE ... and so on). The reduce only constructs the Q object, which doesn't hit the database.
from functools import reduceob_list = data.objects.filter(name__in=my_list)
And BTW, avoid using the variable name "list" (Or any other python standard keyword), lest you get into some weird bugs later.
Update: (I guess your question was updated too, because when I wrote the answer, I didn't see the part where you wrote you need a contains match and not an exact match)
You can do that using the regex search too, avoiding many Q expressions (which end up using that many where "and" clauses in the SQL, possibly dampening the performance), as follows:
data.objects.filter(name__regex=r'(word1|word2|word3)')
obj_list = [obj for obj in data.objects.all() if any(name in obj.name for name in list)]
Edit: Just re-read your question. Don't know if you can do that with filter but you can do it with a list comprehension or generator expression.
For anyone comparing Arrays, you could use Django's Overlap filter to achieve this.
From the docs:
Returns objects where the data shares any results with the values passed. Uses the SQL operator &&.
So, you would simply write:
ob_list = data.objects.filter(name__overlap=my_list)
very simple just use "__in" , as the follwing :
my_list= ['word1','word2','word3']
ob_list = model.objects.filter(your-field__in=my_list)
1- change "model" by your model name.
2- change "your-field" by your field name.
i hope this helpful .
Just thought I would add this here. Built this off the "use Q objects" answer with a little tweaking to get search to work for multiple partial word matches across specified fields.
from functools import reduce
from django.contrib.postgres.search import SearchVector
from django.db.models import Q
s = "Input text to match to fields in SearchVector"
words = list(i for i in s.split(" "))
search_data = (
Item.objects.annotate(
search=SearchVector(
"id",
"name",
),
)
.filter(
reduce(
lambda x, y: x & y,
[Q(search__contains=word) for word in words],
)
)
.all()
)
