Django, how to use filter to check if string field is contained in parameter

Question

Say, I have a model with a text field:

class SomeModel
    keyword=models.CharField(null=True, max_length=255)

Now, I know how to check if

Answer 1

You'll have to split your input into words (depending on your definition of "word"), and then iterate over them, concatenating the various resulting querysets (most of which are likely to be empty).

To split, you could use a regex, catching all letters and the apostrophe (but you'll miss a smart-quote, if someone uses that as input instead of the standard ASCII apostrophe):

words = re.split(r"[^A-Za-z']+", querystring)

Then loop and filter:

query = Q()  # empty Q object
for word in words:
    # 'or' the queries together
    query |= Q(keyword_icontains=word)
results = SomeModel.objects.filter(query).all()

The above code is untested, and I got the idea to 'or' the queries and an empty Q() from this answer.

Depending on your next step(s), evaluating the query directly in each loop step, appending to a results list, might work better for you (using e.g. itertools.chain, as per this answer).

Answer 2

Here is a solution that will select SomeModel rows whose keyword is any substring of the querystring, not just complete words:

SomeModel.objects\
    .annotate(querystring=Value(querystring, output_field=CharField()))\
    .filter(querystring__icontains=F('keyword'))

See docs for info about annotate, Value expressions and F expressions