warnings and its print method print the
variable last.warning in a pleasing form.
warnings(...)cat."warnings", basically a named
list.
last.warning is stored nor that it is
visible, and this is subject to change.options("warn") for the
circumstances under which there is a last.warning object and
warnings() is used. In essence this is if options(warn =
0) and warning has been called at least once. It is possible that last.warning refers to the last recorded
warning and not to the last warning, for example if options(warn) has
been changed or if a catastrophic error occurred.
warning.
## 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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