[R] "subscript out of range" message

[arinbasu@softhome.net]

Hi All: 

I was recently working with a dataset on arsenic poisoning. Among the 
variables in the dataset, I used the following three variables to produce 
crosstabulations (variable names: FOLSTAT, GENDER, ASBIN; all three were 
categorical variables, FOLSTAT denoted follow up status for the subjects and 
had seven levels, GENDER denoted sex (two levels: male,female), and ASBIN 
denoted binarized arsenic concentrations (two levels: "<0.05", ">0.05" 
denoting less than 0.05 mg/L and more than 0.05 mg/L respectively). 

To illustrate, I used the following code for crosstabulation: 

x <- table(FOLSTAT,GENDER,ASBIN) 

# from the results, I then wanted to subset a table for the ASBIN
value ">0.05" 

I used the following code to subset the table: 

y <- x[,,ASBIN=">0.05"] 

# When I do this, R throws an error message stating "subscript out of 
range". However, it runs fine if I change the labels for my ASBIN variable 
from "<0.05" and ">=0.05" to words like "Nonexposed" and "Exposed" 
respectively. 

I searched the archives and the documentations for this, but could not find 
a solution. I understand that sometimes it is more expressive to use 
expressions like "<0.05" (or something similar) as headings in 
cross-tabulations. What was I doing incorrectly? 

Would greatly appreciate your insight. 

I use:
R version: 1.7.1
OS: Windows XP Home 

TIA,
Arin Basu