[BioC] Retrieving SNP rs IDs using biomaRt getBM()

[Sonia Shah [guest]]

I have a list of chromosomal positions for which I would like to retrieve SNP rs IDs (if present at these locations). I used the following code to try and get the rs IDs at 2 locations.

getBM(
attributes=c("refsnp_id","chr_name","chrom_start"),
filters=c("chr_name","chrom_start","chrom_end"), values=list(c(19,19), c(45412079,45415640), c(45412079,45415640)), mart)

I get back the rs IDs for these 2 locations but also get a list of snps that lie within these 2 positions (a total of 82 SNPs are returned with this query).

How do I query the database to return only the rs ids at the 2 specified chromosomal positions?

Many thanks
Sonia

 -- output of sessionInfo(): 

R version 2.11.1 (2010-05-31) 
x86_64-redhat-linux-gnu 

locale:
 [1] LC_CTYPE=en_US.iso885915       LC_NUMERIC=C                  
 [3] LC_TIME=en_US.iso885915        LC_COLLATE=en_US.iso885915    
 [5] LC_MONETARY=C                  LC_MESSAGES=en_US.iso885915   
 [7] LC_PAPER=en_US.iso885915       LC_NAME=C                     
 [9] LC_ADDRESS=C                   LC_TELEPHONE=C                
[11] LC_MEASUREMENT=en_US.iso885915 LC_IDENTIFICATION=C           

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base     

other attached packages:
[1] biomaRt_2.4.0

loaded via a namespace (and not attached):
[1] RCurl_1.91-1 tools_2.11.1 XML_3.9-4   

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