refseq: Retrieve reference sequences (XStringSet-class) from object.
Description
This is the suggested method for accessing the
phylogenetic tree,
(XStringSet-class) from a
phyloseq data object (phyloseq-class). Like
other accessors (see See Also, below), the default
behavior of this method is to stop with an error if
physeq is a phyloseq-class but does not
contain reference sequences (the component data type you
are trying to access in this case).
Usage
refseq(physeq, errorIfNULL=TRUE)
Arguments
physeq
(Required). An instance of phyloseq-class
that contains a phylogenetic tree. If physeq is a
phylogenetic tree (a component data class), then it is
returned as-is.
errorIfNULL
(Optional). Logical. Should the
accessor stop with an error if the slot is empty
(NULL)? Default TRUE.
Value
The phylo-class object contained
within physeq; or NULL if physeq does not
have a tree. This method stops with an error in the
latter NULL case be default, which can be over-ridden by
changing the value of errorIfNULL to FALSE.