By the way, there are tools to retrieve a certain range from compressed data, which IMHO is a very cool feature of gzip. https://www.htslib.org/doc/bgzip.html https://www.htslib.org/doc/tabix.html Bioinformaticians use it (among other things) for fast retrieval of genomic annotation from data sets with on the order of 10^9 keys (in case of human genome). Would be nice if someone wrote a Haskell binding. Olaf
Hello,
I have a question regarding 'Data.Map' api, filed an issue https://github.com/haskell/containers/issues/708
And may be I can ask here at the same time?
I'm not sure why|Data.Map|doesn't have a key range based visiting API, I figured out I can do it this way:
|indexKeyRange :: IndexKey -> IndexKey -> Map IndexKey Object -> [(IndexKey, Object)] indexKeyRange !minKey !maxKey = toList . takeWhileAntitone (<= maxKey) . dropWhileAntitone (< minKey) |
But wouldn't it save the computation needed to re-balance the intermediate tree generated ? Or that re-balancing can be optimized out actually ?
I am creating an in-memory graph database, using|Data.Map.Strict.Map|as business object indices with specified object attributes. The typical scenario will be querying a small number of entries by key range, out of possibly all business objects of a certain class globally, so the implementation above would work, but not reasonable by far as it seems.
I think a lazy list returned by mere node visiting (i.e. no new node creation) would satisfy my needs, or I missed something ?
Thanks,
Compl