procedure ngrams: n-grams with count procedure ngramset: n-grams set
link ngrams
March 20, 1998; Ralph E. Griswold
This file is in the public domain.
The procedure ngrams(s, n, c, t) generates a tabulation of the n-grams in the specified string. If c is non-null, it is used as the set of characters from which n-grams are taken (other characters break n-grams). The default for c is the upper- and lowercase letters. If t is non-null, the tabulation is given in order of frequency; otherwise in alphabetical order of n-grams. For backward compatibility, the first argument may be a file, in which case, it is read to provide the string.