ifelse question

jropers at freesurf.fr wrote:

What is puzzling me is that rnorm(1) is only evaluated *twice*, one 
time for each branch, with only 2 different random deviates, instead 
of giving ten different random deviates. y1 has indeed 10 values but 
with only 2 different ones.
  

I find it more puzzling why you expect that ifelse,  a function of 
three vector arguments, would cause its input arguments to be 
reevaluated for  every element of the result.

I would like to have rnorm be evaluated for each row and collect ten 
*different* random deviates.

y1
 [1] 0.4087172 0.7707796 0.4087172 0.4087172 0.7707796 0.4087172 
0.4087172
 [8] 0.7707796 0.7707796 0.4087172


Thanks.

Jacques.