survival curve for only certain values of a factor

Chang Liu <changisme <at> hotmail.com> writes:

data(aml)
If I use instead dummy variables:

aml$x1 = (aml$x=="maintained")aml$x2 = (aml$x=="unmaintained")
and I want to plot the survival curve using x1, x2, and I just want the 2

levels, rather than 4 curves from:

I don's understand what you want, but the first step is definitively incorrect
apart from the missint line break. The levels of aml are

"Maintained","Nonmaintained"

so both your "==" lead to all-false levels.

Dieter