r - Display names of column of recursive list as tree -

is there (built'in/easy) way recursively display names of interlinked list tree? (with possibly output similar tree shell command. )

for instance list x, 2 column , b, consiting in 2 subcolumn a1 , a2

nametree(x) x ├── │   ├── a1 │   └── a2 └── b 

names(x) display [1] "a" "b"

here recursive solution:

nametree <- function(x, prefix = "")   if( is.list(x) )     for( in seq_along(x) ) {        cat( prefix, names(x)[i], "\n", sep="" )       nametree(x[[i]], paste0(prefix, "  "))     } x <- list(x = list( = list( a1=1:10, a2=1:10 ), b = 1:10 )) nametree(x) # x #   #     a1 #     a2 #   b 

displaying tree structure branches rather spaces trickier:

nametree <- function(x, prefix1 = "", prefix2 = "", prefix3 = "", prefix4 = "")   if( is.list(x) )     for( in seq_along(x) ) {        cat( if(i<length(x)) prefix1 else prefix3, names(x)[i], "\n", sep="" )       prefix <- if( i<length(x) ) prefix2 else prefix4       nametree(         x[[i]],          paste0(prefix, "├──"),         paste0(prefix, "│  "),         paste0(prefix, "└──"),         paste0(prefix, "   ")       )     } nametree(x) # x # +--a # ¦  +--a1 # ¦  +--a2 # +--b # +--c #    +--a #    +--b