The MEDLINE N-gram Set 2016: by Split, Group, Filter, and Combine Algorithm

The MEDLINE n-gram set (generated by split, group, filter, and combine algorithm) is listed as bellows. For each MEDLINE record, title and abstract are used as the source of n-grams. They are combined, tokenized into sentences, and then tokenized into tokens (words use space as word boundary). Finally, n-grams are generated by filtering out terms with more than 50 characters or the total word count is less than 30. The specifications of generating these n-grams are listed as follows:

  • MEDLINE: 2016 - TI and AB (from MEDLINE Baseline Repository - MBR, PmidTiAbS16nXXXX.txt: 1 ~ 812)
  • Method: Split, Combine, Filter Algorithm
  • Max. Character Size: 50
  • Min. word count: 30
  • Min. document count: 1

  • Total document count: 24,358,442
  • Total sentence count: 143,471,776
  • Total token count: 2,971,013,236

  • N-gram files
    • File format - 3 fields:
      Document countWord countN-gram
    • Sorted by document count, word count, then alphabetic order of n-grams. N-gram set is not sorted. It can be sorted by nGramUtil package.


    N-gramsFileZip SizeActual SizeNo. of n-grams
    Unigrams1-gram.2016.tgz5.9 MB15 MB883,287
    Bigrams2-gram.2016.tgz37 MB109 MB5,114,547
    Trigrams3-gram.2016.tgz55 MB182 MB7,134,807
    Four-grams4-gram.2016.tgz38 MB132 MB4,380,474
    Five-grams5-gram.2016.tgz18 MB64 MB1,812,223
    N-gram SetnGramSet.2016.30.tgz153 MB499 MB19,325,338
    Distilled N-gram SetdistilledNGram.2016.tgz60 MB191 7,402,848