is_subtree_rooted_at: Checks if a tree is rooted at a node of another tree.
In autoharp: Semi-Automatic Grading of R and Rmd Scripts

Description Usage Arguments Details Value Examples

This function checks if a given tree is a sub-tree of another tree at a particular node.

1	is_subtree_rooted_at(x, y, at_node)

`x`	An object of class TreeHarp.
`y`	An object of class TreeHarp.
`at_node`	An integer, corresponding to a node in object y. The sub-tree of y, rooted at at_node, is compared to x.

Here's how it works: The sub-tree of y, rooted at at_node is first extracted. The tree x is then compared to this. If x is a sub-tree of it, then this function returns FALSE. Otherwise it returns TRUE.

A logical value indicating if x is a sub-tree of y, rooted at at_node.

thb1 <- TreeHarp(list(b=2, d=NULL))
tha1 <- TreeHarp(list(a=c(2,3), b=4, c = NULL, d=NULL))
is_subtree_rooted_at(thb1, tha1, 1) # FALSE
is_subtree_rooted_at(thb1, tha1, 2) # TRUE