ProjectiveDependencyParser.concatenate(span1, span2)[source]

Concatenates the two spans in whichever way possible. This includes rightward concatenation (from the leftmost word of the leftmost span to the rightmost word of the rightmost span) and leftward concatenation (vice-versa) between adjacent spans. Unlike Eisner’s presentation of span concatenation, these spans do not share or pivot on a particular word/word-index.

Returns:A list of new spans formed through concatenation.
Return type:list(DependencySpan)