R help - Nov 2013 - constucting a sub-network based on time period

A sample of my data looks like this.

Header: Time Sender Receiver



          1    1       2

          1    1       3

          2    2       1

          2    2       1

          3    1       2

          3    1       2

There are 3 time periods (sessions) and the edgelists between nodes.



I tried to write the code for subsetting data (for constructing a network)
based on time  period as follows:


>uniq <-unique(unlist(df$Time))

>uniq [1] 1 2 3

>t=list()

>net=list()

>g=list()

>for (i in 1:length(uniq)) {

>t[[i]]<-subset(df, Time==uniq[i])

>t[[i]] <-as.matrix(t[[i]])

>net[[i]]<-t[[i]][,-1] #removing time column


# getting edgelist
>net[[i]][,1]=as.character (net[[i]][,1])

>net[[i]][,2]=as.character (net[[i]][,2])

>g [[i]]=graph.edgelist (net [[i]], directed=T)

>g [[i]] }


however, I've got an error message (expect two columns).I am kind of new to
R so it is hard to figure it out.  I guess t[i] is the problem.

Is there anyone who can find my logical or syntax error in the code?



Jinie

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