Print a tree's data structure

ptree: the same tree plot.tda_graph draws (via pltree), but as data rather than a picture – one row per node, its parent, its first child, and its next sibling, the linked-list representation TDA itself builds internally to draw one.

Usage

tda_ptree(g, root = NULL, options = list(), dir = tempfile("tda"), ...)

Arguments

g

a tda_graph, undirected and shaped like a tree.

root

which node to treat as the root; the first node in g's data by default.

options

a named list of further TDA options, passed through.

dir

working directory.

...

passed to tda_run.

Value

A data frame: node, edge_from, edge_to, value, parent, first_child, next_sibling (0 where a node has none).

Details

TDA's gn= (which graph, when more than one is open) is not optional here in practice: ptree, unlike pltree, never calls the setup step that gives it a safe default, so leaving it out reliably fails with “current graph is not a tree” even for a graph that unambiguously is one (pltree accepts the identical graph) – gn = 1 is always sent explicitly to work around it.

See also

Other graph analysis: plot.tda_graph(), tda_dmet(), tda_g(), tda_g_analyses, tda_graph(), tda_locate_line(), tda_ucl()

Examples

e <- data.frame(from = c(1, 1, 2), to = c(2, 3, 4), value = 1)
g <- tda_graph(e, directed = FALSE)   # 4 nodes, 3 edges: a tree
tda_ptree(g, root = 1)
#>   node edge_from edge_to value parent first_child next_sibling
#> 1    1         2       1     0      0           3            0
#> 2    2         3       1     1      1           4            0
#> 3    3         4       2     1      1           0            2
#> 4    4         0       0     1      2           0            0