## NB this example is intended to be pasted in,
## rather than run by example()
ow <- options("warn")
for(w in -1:1) {
options(warn = w); cat("\n warn =", w, "\n")
for(i in 1:3) { cat(i,"..\n"); m <- matrix(1:7, 3,4) }
}
warnings()
options(ow) # reset
tail(warnings(), 2) # see the last two warnings only (via '[' method)
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