Plot a decision tree with R - r

Question

I have a 440*2 matrix that looks like:
1 144
1 152
1 135
2 3
2 12
2 107
2 31
3 4
3 147
3 0
4 end
4 0
4 0
5 6
5 7
5 10
5 9
The left column are the starting points eg in the app all the 1's on the left would be on the same page. They lead to three choices, pages 144,152,135. These pages can each then lead to another page, and so on until the right hand column says 'end'. What I would like is a way to visualise the scale of this tree. I realise it will be quite large given the nb of rows so maybe not graph friendly, so for clarity I want to know how many possible routes there are in total (from every start point, down every option it gives and the end destinations of each. I realise there will be overlaps but thats why I am finding this hard to calculate).
secondly, each number has an associated title. I would like to have a function whereby if you input a given title it will plot all the possible starting points and their associated paths that will lead there. This should be a lot smaller and therefore graph friendly.
e.g.
dta <- "
14 12 as
186 187 Frac
187 154 Low
23 52 Med
52 11 Lip
15 55 asd
11 42 AAA
42 154 BBB
154 end Coll"
Edited example data to show that some branches are not connected to desired tree
dta <- "
14 12 as
186 187 Frac
187 154 Low
23 52 Med
52 11 Lip
11 42 AAA
42 154 BBB
154 end Coll"
dta <- gsub(" ", ",", dta, fixed = TRUE)
dta <- gsub(" ", ",", dta, fixed = TRUE)
df <- read.csv(textConnection(dta), stringsAsFactors = FALSE, header = FALSE)
names(df) <- c("from", "to", "nme")
library(data.tree)
Warning message:
package ‘data.tree’ was built under R version 3.2.5
tree <- FromDataFrameNetwork(df)
**Error in FromDataFrameNetwork(df) :**
**Cannot find root name. network is not a tree!**
I made this example to show how column 1 leads to a value in column 2 which then refers to a value in column 1 until you reach the end. Different starting points can ultimately lead to different length paths to same destination. so this would look sometigng like:
So here, I wanted to see how you could go from all start points to 'Coll'
greatly appreciate any help

Answer 1

If you have indeed a tree (e.g. no cycles), you can use data.tree:
Start by converting to a data.frame:
dta <- "
14 12 as
186 187 Frac
187 154 Low
23 52 Med
52 11 Lip
15 55 asd
11 42 AAA
42 154 BBB
154 end Coll
55 end efg
12 end hij"
dta <- gsub(" ", ",", dta, fixed = TRUE)
dta <- gsub(" ", ",", dta, fixed = TRUE)
df <- read.csv(textConnection(dta), stringsAsFactors = FALSE, header = FALSE)
names(df) <- c("from", "to", "nme")
Now, convert to a data.tree:
library(data.tree)
tree <- FromDataFrameNetwork(df)
tree$leafCount
You can now navigate to any sub-tree, for analysis and plotting. E.g. using any of the following possibilities:
subTree <- tree$FindNode(187)
subTree <- Climb(tree, nme = "Coll", nme = "Low")
subTree <- tree$`154`$`187`
subTree <- Clone(tree$`154`)
Maybe printing is all you need:
print(subTree , "nme")
This will print like so:
levelName nme
1 154 Coll
2 ¦--187 Low
3 ¦ °--186 Frac
4 °--42 BBB
5 °--11 AAA
6 °--52 Lip
7 °--23 Med
Otherwise, use fancy plotting:
SetNodeStyle(subTree , style = "filled,rounded", shape = "box", fontname = "helvetica", label = function(node) node$nme, tooltip = "name")
plot(subTree , direction = "descend")
This looks like this: