subtree_at: Extract a sub-tree.
In autoharp: Semi-Automatic Grading of R and Rmd Scripts

Description Usage Arguments Details Value Examples

Extracts a sub-tree rooted at a particular node.

1	subtree_at(obj, at_node, preserve_call = FALSE)

`obj`	An object of class TreeHarp
`at_node`	The root of the new sub-tree. An integer, not a label, that corresponds to BFS indexing of the tree.
`preserve_call`	A logical value that indicates if a sub-call should be extracted. This might be slower, but it allows you to evaluate it later.

This is meant for internal use, so the nodeTypes slot is silently dropped, unless preserve_call is set to TRUE

An object of class TreeHarp.

th3 <- list(a= c(2L,3L,4L), b=NULL, c=c(5L, 6L), d=7L, e=NULL, f=NULL, g=NULL)
subtree_at(TreeHarp(th3), 3)
st <- subtree_at(TreeHarp(th3), 4)
plot(st)