Reputation: 791
One field in my model is a charField with the format substring1-substring2-substring3-substring4 and it can have this range of values:
"1-1-2-1"
"1-1-2-2"
"1-1-2-3"
"1-1-2-4"
"2-2-2-6"
"2-2-2-7"
"2-2-2-9"
"3-1-1-10"
"10-1-1-11"
"11-1-1-12"
"11-1-1-13"
For example I need to count the single number of occurrences for substring1. In this case there are 5 unique occurrences (1,2,3,10,11).
"1-X-X-X"
"2-X-X-X"
"3-X-X-X"
"10-X-X-X"
"11-X-X-XX"
Sincerely I don't know where I can start from. I read the doc https://docs.djangoproject.com/en/1.5/ref/models/querysets/ but I didn't find a specific clue.
Thanks in advance.
Upvotes: 0
Views: 715
Reputation: 11048
results = MyModel.objects.all()
pos_id = 0
values_for_pos_id = [res.field_to_check.split('-')[pos_id] for res in results]
values_for_pos_id = set(values_for_pos_id)
How does this work:
results
)pos_id
is your substring index (you have 4 substring, so it's in range 0 to 3)field_to_check
(aka: where you store the substring combinations) on -
(your separator) and fetch the correct substring for that objectThen a simple len(values_for_pos_id)
will do the trick for you
NB: If you don't have pos_id
or can't set it anywhere, you just need to loop like this:
for pos_id in range(4):
values_for_pos_id = set([res.field_to_check.split('-')[pos_id] for res in results])
# process your set results now
print len(values_for_pos_id)
Upvotes: 1
Reputation: 3734
You could loop through these items (I guess they're strings), and add the value of each substring_n to a Set_n.
Since set values are unique, you would have a set, called Set_1
, for example, that contains 1,2,3,10,11.
Make sense?
Upvotes: 0
Reputation: 876
Try something like this...
# Assumes your model name is NumberStrings and attribute numbers stores the string.
search_string = "1-1-2-1"
matched_number_strings = NumberStrings.objects.filter(numbers__contains=search_string)
num_of_occurrences = len(matches_found)
matched_ids = [match.id for match in matched_number_strings]
Upvotes: 0