get.inducedSubgraph and loop function

Question

I have a list containing a network for each row (sna.list.1). For each of the networks, I need to extract a subgraph where only women are included, in order to calculate the density of women-only networks. I have created a loop function to set vertex attributes

female=vector()
for (i in 1 : length (sna.list.1))
  set.vertex.attribute(sna.list.1[[i]],"Female",alter.list.1bis[[i][,"NIDemo1_c4"])

but when I tried to create the subgraph with get.inducedSubgraph I receive a warning message saying " Illegal vertex selection in get.inducedSubgraph". The same formula works if I applied it to just one row/network.

subnetwork2=vector()
for (i in 1 : length (sna.list.1))
subnetwork2[[i]]=get.inducedSubgraph(sna.list.1[[i]],v=which(sna.list.1[[i]]%v%"Female"=="1"))

does anyone have suggestions?

Answer 1

Assuming that get.inducedSubgraph isolated alters is a continuation of your issue, it sounds like you were trying to induce a subgraph of size zero. i.e. v=which(sna.list.1[[i]]%v%"Female"=="1") was returning integer(0) for some networks.

Ideally, since the network package supports networks of size zero (no vertices) get.inducedSubgraph() should return a network of size zero in this case, but it does not yet do that.