sample {base}
What about using instead size = min(5, length(Gpool$SampleNb[Gpool$LngtClas == LngtClas[[4]] & Gpool$SpCode == SpCode[[2]]]) that would make sure your sample is either the size of the data or 5. Sarah On Wed, Jun 5, 2013 at 10:27 AM, Xochitl CORMON
<Xochitl.Cormon at ifremer.fr> wrote:
Hi all,
I'm trying to randomly select sample numbers for length class groups (5 per
length class).
For this I'm using a loop FOR and the function sample () and specified a
size for the sampling of 5. Unfortunately, one of the length class group
does not contain 5 individuals. For me is not a big deal as I have others
groups to complete. However it bothers me that the sampling function does
not select any individuals in this group generating the error below :
Error in sample(Gpool2$SampleNb[Gpool2$LngtClas == LngtClas[[i]] &
Gpool2$SpCode == : can not take a sample larger than the population when
'replace = FALSE'.
I understand why this error message appears but I was wondering if there is
a way to select all the items present in the group even if it's not 5
(something like size =< 5).
LngtClas <- list( "40_49", "50_59", "60_69", "70_")
SpCode <- list ("POLLVIR ", "MERLMER")
a <- as.character(sample(Gpool$SampleNb[Gpool$LngtClas == LngtClas[[4]] &
Gpool$SpCode == SpCode[[2]]], size = 5, replace = FALSE))
You can find enclosed my dataset,
Thank you for the help,
Xochitl C.
Sarah Goslee http://www.functionaldiversity.org