Hi,
I have a question concerning the selection of data. Let's say that given
list h created below, I would like to select a section of the 1999 matrix.
For a case (rownames and colnames) I would like to select the cells that
have a value > 0. So for case 8025
8025 8026 8027
8025 1 1 1
8026 1 1 1
8027 1 1 1
And for case 8028
8028 8029
8028 1 1
8029 1 1
DF2 = data.frame(read.table(textConnection(" A B C
80 8025 1995
80 8026 1995
80 8029 1995
81 8026 1996
82 8025 1997
82 8026 1997
83 8025 1997
83 8027 1997
90 8026 1998
90 8027 1998
90 8029 1998
84 8026 1999
84 8027 1999
85 8028 1999
85 8029 1999"),head=TRUE,stringsAsFactors=FALSE))
e <- function(y) crossprod(table(DF2[DF2$C %in% y, 1:2]))
years <- sort(unique(DF2$C))
f <- as.data.frame(embed(years, 3))
g<-lapply(split(f, f[, 1]), e)
h<-lapply(g, function (x) ifelse(x>0,1,0))# These are the adjacency matrices
per year
h
Thanks very much!
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