a survival object, generated from the
survfit or
survexp functions.
OPTIONAL ARGUMENTS:
type
the line type, as described in
lines. The default is a step function
for
survfit objects, and a connected line for
survexp objects.
mark,col,lty,lwd
vectors giving the mark symbol, color, line type and line width for the
added curves.
mark.time
controls the labeling of the curves.
If
FALSE, no labeling is done.
If
TRUE, then curves are marked at each censoring time.
If
mark.time is a numeric vector,
then curves are marked at the specified time points.
xscale
a number used to divide the x values. If time was originally in days, a
value of 365.24 would give a plotted scale in years.
firstx,firsty
the starting point for the survival curves. If either of these is set to
NA or the plot will start at the first time point of the curve.
xmax
the maximum horizontal plot coordinate.
This shortens the curve before plotting it, so unlike using the
xlim graphical parameter, warning messages about out of bounds points are
not generated.
fun
an arbitrary function defining a transformation of the survival curve.
For example
fun=log is an alternative way to draw a log-survival curve
(but with the axis labeled with log(S) values).
Four often used transformations can be specified with a character
argument instead: "log" is the same as using the
log=T option,
"event" plots cumulative events (f(y) = 1-y),
"cumhaz" plots the cumulative hazard function (f(y) = -log(y))
and "cloglog" creates a complimentary log-log survival plot
(f(y) = log(-log(y) along with log scale for the x-axis).
conf.int
if
TRUE, confidence bands for the curves are also plotted.
If set to "only", then only the CI bands are plotted, and the curve
itself is left off.
This can be useful for fine control over the colors or line types of a plot.
VALUE:
a list with components x and y, containing the coordinates of the last point
on each of the curves (but not of the confidence limits).
This may be useful for labeling.
SIDE EFFECTS:
one or more curves are added to the current plot.
SEE ALSO:
,
,
,
,
.
EXAMPLES:
# First select by "id" those elements with the greater value of "stop"
hearta <- by(heart, heart$id, function(x) x[x$stop==max(x$stop),])
# Make the resulting list into a data frame by rebinding its components
hearta <- do.call("rbind", hearta)
# Plot the fitted survival curves
plot(survfit(Surv(stop, event) ~ surgery, data=hearta), lty=1:2)
# Add lines denoting the expected survival from National Rate Table
lines(survexp (stop ~ surgery + ratetable(age=(age + 48)*365.25,
sex="male", year=year*365.25), data=hearta), mark="E",
mark.time=1000, lty=1:2, cex=1.5)