Iterating through two lists of objects Python

Question

I have two long lists of objects in Python: queries_list (list of Query objects) and results_list (list of Result objects)

I'd like find Result objects that are related to a Query, using a common field 'search_id', then I should append related results to Query.results list.

The pseudocode is as below:

for q in  queries_list
   for r in results_list
       if q.search_id == r.search_id
           q.results.append(r)

It looks like you already have a working solution - what exactly is the question here? Are you looking for a better way? A faster/more efficient way? — Peter Gibson
– Peter Gibson, Commented Mar 22, 2015 at 0:23

torkil · Accepted Answer · 2015-03-22 00:34:28Z

1

Your pseudocode is almost python-code, but here is a python variant using filter.

for query in queries_list:
   hasQueryId = lambda result: result.search_id == query.search_id
   query.results.extend(filter(hasQueryId, results_list))

This should result in all your queries result-lists being populated. This is still O(m*n), if you're looking for more efficient ways Id try sorting the results and queries by id.

answered Mar 22, 2015 at 0:34

torkil

1115 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

avacariu · Accepted Answer · 2015-03-22 01:50:07Z

1

Your pseudo-code is almost Python. You're just missing colons:

for q in queries_list:
   for r in results_list:
       if q.search_id == r.search_id:
           q.results.append(r)

This is assuming your query objects already have results attributes.

If not, you can create them at runtime:

for q in queries_list:
   for r in results_list:
       if q.search_id == r.search_id:
           try:
               q.results.append(r)
           except AttributeError:
               q.results = [r]

answered Mar 22, 2015 at 1:50

avacariu

2,9183 gold badges27 silver badges25 bronze badges

Collectives™ on Stack Overflow

Iterating through two lists of objects Python

2 Answers 2

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related