Convert a List of Distances to a Distance Matrix

x <- read.table(textConnection("A A 0

closeAllConnections()
# get the unique names
x.names <- sort(unique(c(x[[1]], x[[2]])))
# create a matrix of the right size and put names on it
x.dist <- matrix(0, length(x.names), length(x.names))
dimnames(x.dist) <- list(x.names, x.names)
# create indices by converting names to numbers and create the normal and reversed
# to fill in all the matrix
x.ind <- rbind(cbind(match(x[[1]], x.names), match(x[[2]], x.names)),

x.dist[x.ind] <- rep(x[[3]], 2)
x.dist

Hello,

Is there an easy function for switching list to matrix. My list is of
genetic distances between species pairs:

A A 0
A B .5
A C .25
B C .5

and I want a distance matrix such as:

  A  B  C
A 0  .5 .25
B .5  0 .5
C .25 .5 0

for use in a mantel test.

Thank you for the help!

cheers,
charlie

--
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Charles G. Willis
Department of Organismic and Evolutionary Biology
22 Divinity Ave Cambridge MA 02139
HP (857) 488-2506
WP (617) 496-3890
cgwillis at oeb.harvard.edu
http://www.people.fas.harvard.edu/%7Ecgwillis/
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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