Sankey diagram in R

Question

Attempting to make a fairly generic Sankey diagram with the help of R's networkD3 package. Just for reference--here's the example from the package's manual

library(networkD3)
library(jsonlite)
library(magrittr)

energy <- "https://cdn.rawgit.com/christophergandrud/networkD3/master/JSONdata/energy.json" %>% 
      fromJSON

sankeyNetwork(Links = energy$links, 
              Nodes = energy$nodes, 
              Source = "source",
              Target = "target", 
              Value = "value", 
              NodeID = "name",
              units = "TWh", 
              fontSize = 12, 
              nodeWidth = 30)

which results in:

My fairly straightforward extension consists of building a diagram with the following underlying data:

links <- structure(list(source = structure(c(1L, 2L, 3L, 1L, 2L, 3L, 4L, 
                                         5L, 4L, 5L),
                                       .Label = c("1", "2", "3", "4", "5"),
                                       class = "factor"), 
                    target = structure(c(1L, 1L, 1L, 2L, 2L, 2L, 3L, 3L, 4L, 
                                         4L),
                                       .Label = c("4", "5", "6", "7"),
                                       class = "factor"), 
                    value = c(88L, 774L, 1220L, 412L, 5335L, 96L, 3219L, 
                              1580L, 111L, 7607L)), 
               row.names = c(NA, 10L), 
               class = "data.frame", 
               .Names = c("source", "target", "value"))

nodes <- structure(list(lab = c("A", "B", "C", "D", "E", "F", "G")),
               row.names = c(NA, -7L),
               .Names = "lab", class = "data.frame")

with this simple application chosen so that my data most closely reflects the manual example. When I run the comparable function, though:

sankeyNetwork(Links = links, 
              Nodes = nodes, 
              Source = "source",
              Target = "target", 
              Value = "value", 
              NodeID = "lab")

Nothing happens. What's my mistake?

Answer 1

This works fine if you start numbering your source and target at 0:

# First coercing elements of links to numeric, so that we can subtract 1
links[] <- lapply(links, function(x) as.numeric(as.character(x)))
links[, 1:2] <- links[, 1:2] - 1
sankeyNetwork(links, nodes, 'source', 'target', 'value', NodeID='lab')