[R] Changing shapes of some Nodes

Hi, I am using the "igraph" package to plot a network. I need most of the vertices to be green and circular. A few selected vertices I need to change to make them blue squares. I created this loop to color the necessary nodes blue but I dont know how to change their shapes: for(i in projectionV.

[R] How are tables accessed?

Hey everyone, I have a small problem understanding how matrices are accessed. I created 2 matrices: data <- structure(c("A", "B", "C", "D", "D", "E", "H", "H", "H", "I", "F", "G", "F", "F", "G", "G", "F", "G", "I", "J"), .Dim = c(10L, 2L), .Dimnames = lis