On Nov 17, 2012, at 4:05 PM, arun wrote:
HI,
If the order of individuals are changed or if some individuals are
missing, this method may need modification.
ind <- c('1','3','4','8')
fam <- c('1','2','1','2')
dat1 <- data.frame(ind,fam)
combn( row.names(dat1), 2, FUN = function(b){
if (dat1[b[1], "fam" ] != dat1[b[2], "fam"] ) { b }
else { c(NA,NA) } } )
# [,1] [,2] [,3] [,4] [,5] [,6]
#[1,] "1" NA "1" "2" NA "3"
#[2,] "2" NA "4" "3" NA "4"
row.names(dat1)<-dat1$ind
combn( row.names(dat1), 2, FUN = function(b){
if (dat1[b[1], "fam" ] != dat1[b[2], "fam"] )
{ b } else { c(NA,NA) } } )
# [,1] [,2] [,3] [,4] [,5] [,6]
#[1,] "1" NA "1" "3" NA "4"
#[2,] "3" NA "8" "4" NA "8"
If you wanted to account for a situation where the row names do not
match the 'ind' names, then you could instead use something like this:
combn( row.names(dat1), 2, FUN = function(b){
if (dat1[b[1], "fam" ] != dat1[b[2], "fam"] ) {
c( dat1[ b[1] ],
"ind"],dat1[ b[2] ], "ind"])
} else { c(NA,NA) }
This should also allow pairs of persons (or chicks or piglets) with
the same name (or id) but from different families to be paired. The
assignment of duplicate names to row.names might produce some
surprises in that instance.
--
David.
A.K.
----- Original Message -----
From: David Winsemius <dwinsem...@comcast.net>
To: benjamin_jarrett <bjmjarr...@gmail.com>
Cc: r-help@r-project.org
Sent: Saturday, November 17, 2012 6:36 PM
Subject: Re: [R] pairing data using combn with criteria
On Nov 17, 2012, at 10:07 AM, benjamin_jarrett wrote:
Hi David,
Thanks for replying. Unfortunately I can't get it to work. Here is
some
(very simplified) data to help illustrate my problem.
ind <- c('1','2','3','4')
fam <- c('1','2','1','2')
data <- data.frame(ind,fam)
ind is the unique ID for each individual, and fam is which family the
individual came from. Using combn(ind, 2) matches all of the
individuals. Is
there any way I could get combn to pair individuals up based on a
different
family number, so with the above data individual 1 would be paired
with
individual 2 or 4.
Please include context (and _do_ read the Posting Guide.) This is
the suggestion I made before:
See if this helps:
combn( 1:5, 2, FUN = function(b){
if (max (b) < 4 ) { b } else { c(NA,NA) } } )
[,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10]
[1,] 1 1 NA NA 2 NA NA NA NA NA
[2,] 2 3 NA NA 3 NA NA NA NA NA
And this is how to apply it to the example:
combn( row.names(data), 2, FUN = function(b){
if (data[b[1], "fam" ] != data[b[2], "fam"] ) { b }
else { c(NA,NA) } } )
[,1] [,2] [,3] [,4] [,5] [,6]
[1,] "1" NA "1" "2" NA "3"
[2,] "2" NA "4" "3" NA "4"
--
David Winsemius, MD
Alameda, CA, USA
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