from <- c("contry", "contry", "race", "race",       "sex",  "sex")
to   <- c(   "sex",   "race", "hair",  "eye", "education",  "age")
vertexnames <- unique(sort(c(from, to)))
vertices <- returnVertexList(vertexnames)
edge.list <- vector("list", length(to))
for (j in seq(along = to)) edge.list[[j]] <- c(from[j], to[j])
edges <- returnEdgeList(edge.list, vertices, color = "red", oriented = TRUE)
graph <- new("dg.graph", vertexList = vertices, edgeList = edges); str(graph)
dg(graph)Run the code above in your browser using DataLab