[R] Please, need help with a plot

[David Winsemius]

On Jan 2, 2011, at 1:15 PM, Ben Bolker wrote:

> Victor F Seabra <vseabra <at> uol.com.br> writes:
>
>>
>>
>>   Please, I wonder if someone knows how to add the
>>   less than or equal to symbol in the plot generated by the code  
>> below:
>>   var1<-c('age <= 3','age <= 7','age <= 10','age <= 11','age <=  
>> 20','age <=
>>   25','age <= 30','age <= 45','age <= 50','age < 55','age >= 55')
>>   var2<-c(3.8,5.4,3.7,3.8,5.9,6.4,7.2,8.4,10.5,1.3,0.7)
>>   table1<-data.frame(var1, var2)
>>   plot(x=table1$var2,y=1:11,xlim=c(0,20),pch=20)
>>   text(x=table1$var2,y=1:11,table1$var1,pos=4)
>>   title(x=15,y=5,expression("how  to  substitute  the  < = with the  
>> " <=
>>   "symbol"),font=5)
>>   Please, note that the data must come from a table (not manually  
>> fed in a
>>   text command)
>>   I received help yesterday and learned a fix using
>>   \u2264, eval, parse, and sprintf  but the symbols generated by  
>> this fix are
>>   not exported to an .EPS file
>>   Kind regards,
>
>
>  This is a little bit more 'magic' than I would like, but seems
> to work. Perhaps someone else can suggest a cleaner solution.

Here's the best I could come up with but will admit that there were  
many failed attempts before success:

expr.vec <- as.expression(parse(text=table1$var1))
plot(x=table1$var2 ,y=1:11, xlim=c(0,20), pch=20)
text(x=table1$var2, y=1:11, labels=expr.vec, pos=4)
title(x=15, y=5, expression("Yet another way to process strings with  
operators like '<=' )

(The title expression works on my machine, but perhaps not on the OP's  
machine, given differences in encoding that have so far been exhibited.)


>
> ages <- gsub("[^0-9]+","",table1$var1)
> rel <- gsub("age\\s*([=<>]+)\\s*[0-9]+","\\1",table1$var1,perl=TRUE)
>
> with(table1,plot(var2,1:11,xlim=c(0,20),pch=20))
> invisible(with(table1,
>     mapply(function(x,y,a,r) {
>       text(x=x,y=y,
>            switch(r,
>                   `<=`=bquote(age <= .(a)),
>                   `<`=bquote(age < .(a)),
>                   `>=`=bquote(age >= .(a))),
>            pos=4)},
>       var2,1:11,ages,rel)))
>
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.

David Winsemius, MD
West Hartford, CT