Hi all, There are 30 samples in my GSE dataset I want to remove some of them but I don know how

Here is me script

series <- "GSE9476"
platform <- "GPL96"
gset <- getGEO(series, GSEMatrix =TRUE, AnnotGPL = TRUE, destdir = "Data/")
if (length(gset) > 1) idx <- grep(platform, attr(gset, "names")) else idx <- 1
gset <- gset[[idx]]

Thanks for any help