Apply a Function to All Nodes of a Dendrogram

Apply function FUN to each node of a dendrogram recursively. When y <- dendrapply(x, fn), then y is a dendrogram of the same graph structure as x and for each node, y.node[j] <- FUN( x.node[j], ...) (where y.node[j] is an (invalid!) notation for the j-th node of y.

dendrapply(X, FUN, ...)
an object of class "dendrogram".
an Rfunction to be applied to each dendrogram node, typically working on its attributes alone, returning an altered version of the same node.
potential further arguments passed to FUN.

  • Usually a dendrogram of the same (graph) structure as X. For that, the function must be conceptually of the form FUN <- function(X) { attributes(X) <- .....; X }, i.e., returning the node with some attributes added or changed.


The implementation is somewhat experimental and suggestions for enhancements (or nice examples of usage) are very welcome. The current implementation is recursive and inefficient for dendrograms with many non-leaves. See the Warning in dendrogram.

See Also

as.dendrogram, lapply for applying a function to each component of a list, rapply for doing so to each non-list component of a nested list.

  • dendrapply
library(stats) require(graphics) ## a smallish simple dendrogram dhc <- as.dendrogram(hc <- hclust(dist(USArrests), "ave")) (dhc21 <- dhc[[2]][[1]]) ## too simple: dendrapply(dhc21, function(n) utils::str(attributes(n))) ## toy example to set colored leaf labels : local({ colLab <<- function(n) { if(is.leaf(n)) { a <- attributes(n) i <<- i+1 attr(n, "nodePar") <- c(a$nodePar, list(lab.col = mycols[i], lab.font = i%%3)) } n } mycols <- grDevices::rainbow(attr(dhc21,"members")) i <- 0 }) dL <- dendrapply(dhc21, colLab) op <- par(mfrow = 2:1) plot(dhc21) plot(dL) ## --> colored labels! par(op)
Documentation reproduced from package stats, version 3.3, License: Part of R 3.3

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