skbio.tree.BPTree.preorder_select

BPTree.preorder_select(k)

Index of the node with a given preorder rank.

Parameters:

kint

Preorder rank to look up, from 1 (the root) to the number of nodes.

Returns:

int

Index of the node whose preorder rank is k, or -1 if k is not a rank of this tree.

See also

preorder_rank

skbio.tree.TreeNode.preorder

Notes

The inverse of preorder_rank. Returns an integer index into the parentheses bit array, not a node object. preorder yields the nodes in this order.

Examples

>>> from skbio.tree import BPTree
>>> tree = BPTree.read(["((a,b)c,(d,e)f)r;"])
>>> [tree.name(tree.preorder_select(k)) for k in range(1, len(tree) + 1)]
['r', 'c', 'a', 'b', 'f', 'd', 'e']
>>> tree.preorder_rank(tree.preorder_select(4))
4
>>> tree.preorder_select(0)
-1