a vector of positioned n-grams (as created by count_ngrams).
Value
A character vector of (n-1)-grams with introduced gaps.
Details
A single element of the input n-gram at a time will be replaced
by a gap. For example, introducing gaps in n-gram 2_1.1.2_0.1
will results in three n-grams: 3_1.2_1 (where the 2_1_0 unigram
was replaced by a gap), 2_1.2_2 and 2_1.1_0.