igraph problem with verteces

Hi,
guys my question is simple, why when I created a graph with edges like 3-5 and 5-7, the vertices are 7?

#U: is a vector with the name of vertex like 2-3-5-7 and list_edges is useful to check a condition that I supposed
edges.U <- function(U, list.edges){ 
  edges <- c()
  
  `%notin%` <- Negate(`%in%`) #define new operator
  for(row in 1:nrow(list.edges)){
    if( (list.edges[row, 1] %in% U) && (list.edges[row, 2] %notin% U) ){
      edges <- append(edges, c(list.edges[row, 1], list.edges[row, 2]) )
    }
  }
   #here I created correctly the edges vector, in this case I had 3-5 and 5-7
  subgraph.U <- graph(edges, U, directed=F) #####ERROR
  return(subgraph.U)
}

In this case, why my vertices are wronged...?
How to set verteces with the function graph() by igraph?

kind regards, to the answer

This topic was automatically closed 21 days after the last reply. New replies are no longer allowed.

If you have a query related to it or one of the replies, start a new topic and refer back with a link.