The MEDLINE N-gram Set

The MEDLINE N-gram Set 2015: 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: 2015 - TI and AB (from MEDLINE Baseline Repository - MBR, PmidTiAbS15nXXXX.txt: 1 ~ 779)
• Method: Split, Combine, Filter Algorithm
• Max. Character Size: 50
• Min. word count: 30
• Min. document count: 1

• Total document count: 23,343,329
• Total sentence count: 134,834,507
• Total token count: 2,786,085,158

• N-gram files
  • File format - 3 fields:

    Document count

    Word count

    N-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.

  Download:

  N-grams	File	Zip Size	Actual Size	No. of n-grams
  Unigrams	1-gram.2015.tgz	5.7MB	14MB	843,206
  Bigrams	2-gram.2015.tgz	35MB	103MB	4,845,965
  Trigrams	3-gram.2015.tgz	52MB	171MB	6,702,194
  Four-grams	4-gram.2015.tgz	35MB	123MB	4,082,612
  Five-grams	5-gram.2015.tgz	17MB	59MB	1,674,715
  N-gram Set	nGramSet.2015.30.tgz	143MB	467MB	18,148,692
  Distilled N-gram Set	distilledNGram.2015.tgz	55MB	176MB	6,793,561