CODEWITHSUNDEEP
rgraphigraph
NewUsr_stat
NewUsr_stat

Reputation: 2571

Error with igraph library

I'm trying to use the following R library: iSubpathwayMiner that requires the following packages: graph, igraph, RBGL. While running the string 

graphList<-getMetabolicECECGraph()

that you can find in the vignette, the following Error I'm not able to manage occurs: 

#    Error in if (get.vertex.attribute(graphList[[i]], "type", j - 1) %in%  : 
#      argument is of length zero

Can anyone help me at least to try to understand what does it means and how to manage it?

Thank you in advance

Best

Upvotes: 1

Views: 945

Answers (1)

Rusan Kax
Rusan Kax

Reputation: 1894

The error is saying that the argument of the if is NULL. This most likely arises because your graph does not have an attribute named type. There are errors and other unresolved conflicts with these libraries, so it is not possible to rule anything else out.

You can run this example in a R session

library(igraph)
g <- graph.ring(10)
g <- set.graph.attribute(g, "name", "RING")
g <- set.vertex.attribute(g, "color", value=c("red", "green"))

get.vertex.attribute(g, "color")
#>[1] "red"   "green" "red"   "green" "red"   "green" "red"   "green" "red"   "green"

#Asking for an attribute that does not exist will return NULL
get.vertex.attribute(g, "day")
#>NULL

#And 
if(NULL){print(1)}
#>Error in if (NULL) { : argument is of length zero

#so
if(get.vertex.attribute(g, "day") %in% c("Mon","Tue","Wed")){print("doSomething")}
#>Error in if (get.vertex.attribute(g, "day") %in% c("Mon", "Tue", "Wed")) { : 
#argument is of length zero

In general, you should check that an argument of an if statement is not NULL by using something like is.null() beforehand.

Upvotes: 1

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