[R] vectorising ifelse()

Federico Calboli f.calboli at imperial.ac.uk
Fri Jul 22 01:44:08 CEST 2005

Hi All,

is there any chance of vectorising the two ifelse() statements in the
following code:

for(i in gp){
   new[i,1] = ifelse(srow[i]>0, new[srow[i],zippo[i]], sample(1:100, 1,
prob =Y1, rep = T))
   new[i,2] = ifelse(drow[i]>0, new[drow[i]>0,zappo[i]], sample(1:100,
1, prob =Y1, rep = T))

Where I am forced to check if the value of drow and srow are >0 for each
line... in practical terms, I am attributing haplotypes to a pedigree,
so I have to give the haplotypes to the parents before I give them to
the offspring. The vectors *zippo* and *zappo* are the chances of
getting one or the other hap from the sire and dam respectively. *gp* is
the vectors of non-ancestral animals. *new* is a two col matrix where
the haps are stored.



Federico C. F. Calboli
Department of Epidemiology and Public Health
Imperial College, St Mary's Campus
Norfolk Place, London W2 1PG

Tel  +44 (0)20 7594 1602     Fax (+44) 020 7594 3193

f.calboli [.a.t] imperial.ac.uk
f.calboli [.a.t] gmail.com

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