[R] legend

[David Winsemius]

On Sep 22, 2010, at 2:58 PM, David Winsemius wrote:

>
> On Sep 22, 2010, at 1:39 PM, threshold wrote:
>
>>
>> Hi,
>> there is a function to plot survival curves:
>>
>> library(survival)
>> plot.KM <- function(survival, x, x_cut.off, main='', label='')
>> {
>> plot(survfit(survival ~ I(x >= x_cut.off)), main=main)
>> legend('bottomleft', c(expression(label >=  
>> x_cut.off),expression(label <
>> x_cut.off)))
>> }
>
> This is untested because "survival" is not an object for the rest of  
> us to survfit:
>
> plot.KM <- function(survival, x, x_cut.off, main='', label='')
> {
> #really kind of worried about whether this part will work, but  
> perhaps you already have this running?
> plot(survfit(survival ~ I(x >= x_cut.off)), main=main)
> #####
> ## perhaps something like this ... untested d/t no data example
> legend('bottomleft',
>       labels= bquote( .(label)>=.(x_cut.off),
>       ^^no^^          .(label)<.(x_cut.off) ) )
(labels is a argument to text() but not to legend().


That should be :
  legend('bottomleft',
       legend= bquote( .(label)>=.(x_cut.off),
                       .(label)<.(x_cut.off) ) )


> }
>
> (And if you have made such a Surv object, perhaps naming it  
> something other than the package name would be less confusing to us  
> ordinary mortals.)
>
> -- David.
>
>
>
>>
>> Now, I need to determine as the argument what appears in the  
>> legend. I want
>> plot.KM(survival, x, x_cut.off=0.5, main='', label='ABC')
>> but what I get is ('label < x_cut.off') in legend instead of  
>> 'ABC<0.5'.
>> Symbol '>=' should be in mathematical form. will appreciate any help.
>>
>> robert
>>
>


David Winsemius, MD
West Hartford, CT