Are a specified set of nodes in a graph connected? - r

I'm new to using graphs in R, and haven't been able to find a solution to this problem. Take a simple graph
library(igraph)
df <- data.frame(a = c("a","a","a","b","c","f"),
b = c("b","c","e","d","d","e"))
my.graph <- graph.data.frame(df, directed = FALSE)
plot(my.graph)
What I want is to be able to define a function which takes the graph and a set of nodes as arguments and for a logical output as to whether those nodes are connected. For example
my.function(my.graph, c("b", "a", "c"))
# TRUE
my.function(my.graph, c("b", "a", "e"))
# TRUE
my.function(my.graph, c("b", "a", "f"))
# FALSE
Any help appreciated

You are just asking if the induced subgraph is connected, so compute the subgraph and test if it is connected.
my.function = function(g, nodes) {
is_connected(subgraph(g, nodes)) }
my.function(my.graph, c("b", "a", "c"))
[1] TRUE
my.function(my.graph, c("b", "a", "e"))
[1] TRUE
my.function(my.graph, c("b", "a", "f"))
[1] FALSE

Related

R networkD3 package: edge coloring in simpleNetwork()

Is there a way to colour the edges of the network using the package networkD3 in R? All I have seen is ways of colouring the nodes but I have not seen anything regarding colouring the edges? Thanks
see the help file with ?simpleNetwork
it describes all the possible arguments, including...
linkColour - character string specifying the colour you want the link lines to be. Multiple formats supported (e.g. hexadecimal).
library(networkD3)
Source <- c("A", "A", "A", "A", "B", "B", "C", "C", "D")
Target <- c("B", "C", "D", "J", "E", "F", "G", "H", "I")
NetworkData <- data.frame(Source, Target)
simpleNetwork(NetworkData, linkColour = "green")

Recursive function to check all possible paths (from raw material to product)

I am struggling with a recursive function, who's goal is to determine which raw materials belong to which product. I clouldn't figure out, how to handle multiple possible paths in data frame "db". The wanted function should give: A-B-C-E, A-B-C-F, A-B-D-F for db. My function works for "da". I added it to show what I am after, and it is a bit like bill of materials explosion, but not exactly.
da <- data.frame(parent = c("A", "B", "B", "C", "D"),
child = c("B", "C", "D", "E", "F"),
stringsAsFactors = FALSE)
db <- data.frame(parent = c("A", "B", "B", "C", "D", "C"),
child = c("B", "C", "D", "E", "F", "F"),
stringsAsFactors = FALSE)
my_path <- function(a, df) {
b <- df$parent[df$child == a]
if (length(b) == 0) {
return(a)
} else {
return(c(my_path(b, df), a))
}
}
end_points <- da$child[is.na(match(da$child, da$parent))]
lapply(end_points, function(x) my_path(x, da)) # -> ok
end_points <- db$child[is.na(match(db$child, db$parent))]
lapply(end_points, function(x) my_path(x, db)) # -> not ok
Thx & kind regards
This is a job for igraph:
#the data
db <- data.frame(parent = c("A", "B", "B", "C", "D", "C"),
child = c("B", "C", "D", "E", "F", "F"),
stringsAsFactors = FALSE)
#create a graph
library(igraph)
g <- graph_from_data_frame(db)
#plot the graph
plot(g)
#find all vertices that have no ingoing resp. outgoing edges
starts <- V(g)[degree(g, mode = "in") == 0]
finals <- V(g)[degree(g, mode = "out") == 0]
#find paths, you need to loop if starts is longer than 1
res <- all_simple_paths(g, from = starts[[1]], to = finals)
#[[1]]
#+ 4/6 vertices, named, from 4b85bd1:
#[1] A B C E
#
#[[2]]
#+ 4/6 vertices, named, from 4b85bd1:
#[1] A B C F
#
#[[3]]
#+ 4/6 vertices, named, from 4b85bd1:
#[1] A B D F
#coerce to vectors
lapply(res, as_ids)

No any plot with networkD3 in R

I tried to run this simple rscript on both RStudio and R x64 but nothing appeared as a result. No plot, nothing... Could someone help please?
# Load package
library(networkD3)
# Create fake data
src <- c("A", "A", "A", "A",
"B", "B", "C", "C", "D")
target <- c("B", "C", "D", "J",
"E", "F", "G", "H", "I")
networkData <- data.frame(src, target)
# Plot
simpleNetwork(networkData)
Code taken by: http://christophergandrud.github.io/networkD3/
I appreciate all your answers! I found a solution that worked to me.
Using the command:
%>% saveNetwork(file = 'File.html')
save an .html file and open it via browser.

Check List to find out all values are same in R

I have list as follows
l = list(c("a", "b", "c"), c("a", "b", "c"), c("a", "b", "c"))
I want to check that each of them contain same values using apply family functions.
I want following answer
TRUE, TRUE, TRUE
We can use duplicated
duplicated(l)|duplicated(l, fromLast=TRUE)
#[1] TRUE TRUE TRUE
If we need to compare all the combinations of list elements, combn is another way
combn(seq_along(l), 2, FUN= function(x) all(l[[x[1]]] == l[[x[2]]]))
#[1] TRUE TRUE TRUE
If you really want to use the apply family, you could do something like:
l = list(c("a", "b", "c"), c("a", "b", "c"), c("a", "b", "c"))
sapply(l, function(x) all.equal(x, l[[1]]))
# returns [1] TRUE TRUE TRUE
l = list(c("a", "b", "c"), c("a", "b", "c"), c("a", "b", "x"))
sapply(l, function(x) all.equal(x, l[[1]]))
# returns [1] "TRUE" "TRUE" "1 string mismatch"

Plot nodes and edges in a coordinate system using R

I implemented the FR test here and now I would like to test it by means of visualizing the resulting minimum spanning trees in R. The vertices and edges should be plotted in a coordinate system.
Moreover I want to set the color for every dot (depending on to which sample it belongs) and express a possible third dimension through the size of the dots.
This is what I have got so far:
library(ggplot2)
nodes <- data.frame(cbind(c("A", "A", "A", "B", "B", "B"), c(1,2,3,8,2,1), c(6,3,1,4,5,6)))
edges <- data.frame(cbind(c("A", "A", "A"), c("A", "B", "B"), c(1,3,2), c(6,1,5), c(2,8,1), c(3,4,6)))
p <- ggplot() +
geom_point(nodes, aes(x=nodes[,2], y=nodes[,3])) +
geom_line(edges)
p
I also think igraph would be best here...
nodes <- data.frame(a=c("A", "A", "A", "B", "B", "B"), b=c(1,2,3,8,2,1),
d=c(6,3,1,4,5,6))
#cbind made your nodes characters so i have removed it here
edges <- data.frame(a=c("A", "A", "A"), b=c("A", "B", "B"), d=c(1,3,2),
e=c(6,1,5), f=c(2,8,1), g=c(3,4,6))
Here is an example using your data as above, to produce the colours colouring with the coordinate layout system coords
library(igraph)
from <- c(rep(edges[,3],3),rep(edges[,4],2),edges[,5])
to <- c(edges[,4],edges[,5],edges[,6],edges[,5],edges[,6],edges[,6])
myedges <- data.frame(from,to)
actors <- data.frame(acts=c(1,2,3,4,5,6,8))
colouring <- sample(colours(), 7)
sizes <- sample(15,7)
coords<-cbind(x=runif(7,0,1),y=runif(7,0,1))
myg <- graph.data.frame(myedges, vertices=actors, directed=FALSE)
V(myg)$colouring <- colouring
V(myg)$sizes <- sizes
plot(myg,vertex.color=V(myg)$colouring,vertex.size=V(myg)$sizes,
layout=coords,edge.color="#55555533")
for plotting a spanning there are also many options, e.g.
d <- c(1,2,3)
E(myg)$colouring <- "#55555533"
E(myg, path=d)$colouring <- "red"
V(myg)[ d ]$colouring <- "red"
plot(myg,vertex.color=V(myg)$colouring,vertex.size=V(myg)$sizes
,edge.width=3,layout=coords,edge.color=E(myg)$colouring )
with axes:
plot(myg,vertex.color=V(myg)$colouring,vertex.size=V(myg)$sizes
,edge.width=3,layout=coords,edge.color=E(myg)$colouring, axes=TRUE )
and use rescale=FALSE to keep original axes scale

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