Hi there,
I would like to ask something about how to avoid a possible error message
within a for loop. I am running a simulation and in some repetitions there may
be an error that will cause a crash and stop the whole procedure, what I want
is to simply move on to the next iteration automatically and discard the "bad"
repetitions from my results. I used the "try" function to do this and it
partially works.
Here is the thing:
logitsboots <- function(x,y,Jbh) {
logitseb=0;logitspb=0;
for (j in 1:1) {
#some code here that has to do with random numbers that may or may not produce
an error and calculates the values of two scalar quantities: spboots and
seboots,
logitspb=log(spboots/(1-spboots))
logitseb=log(seboots/(1-seboots))
#assume that I only care about logitseb for the moment
}
list(lse=logitseb)
}
# Now the following works just fine:
res=0
for(bb in 1:100) {
res[bb] <- try(logitsboots(x,y,Jbh), TRUE)
}
az=unlist(res[sapply(res, function(x) !inherits(x, "try-error"))])
#So far, so good and everything is working fine with "az" having the values of
lse having also discarded the "bad" iterations.
However I would like to store (as an output) both values (logitse AND logitsp)
in the function logitsboots, that is the list would be as :
list(lse=logitseb,lsp=logitspb).
This way the quantity "res" would have two arguments: res$lse and res$lsp each
time it is called. However when an error occures I just cannot seem to manage
to "unlist" the "res" properly since typing "res$lse" for example will warn me
that the "$" operator will not work (since it is not numeric anymore I guess).
Something like the following would fail, but I guess that clears what I want to
do.
az1=unlist(res$lse[sapply(res$lse, function(x) !inherits(x, "try-error"))])
az2=unlist(res$lsp[sapply(res$lsp, function(x) !inherits(x, "try-error"))])
My final goal is to obtain 100 values of lse and 100 values of lsp. (Of course
since the iterations leading to an error would be discarded I will end up with
less than 100 iterations. Any ideas of also using the "while" here in
combination with the "try" to just discard the bad iterations and replace them
with new good ones would be great. This way I would actually get exactly 100
values of lse and lsp).
Most important is to manage to keep both values in a two column matrix or
something. I hope I was clear enough..
Thanx in advance for any answers!
Leo.
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