Extract taxa from a matrix block
ExtractTaxa(matrixLines, character_num = NULL, session = NULL)lines of a file containing a phylogenetic matrix (see ReadCharacters for expected format)
Index of character(s) to return. `NULL`, the default, returns all characters.
(optionally) a Shiny session with a numericInput named character_num whose maximum should be updated.
Matrix with n rows, each named for the relevant taxon, and c columns, each corresponding to the respective character specified in `character_num`