[R] Dynamic file / url name with read.csv

[B S]

Hi- 

I would like to be able to change the value of SymA below and download a file from the corresponding URL.  Hardcoded, this line works fine: 

Symbol<- read.csv("http://ichart.finance.yahoo.com/table.csv?s=SPY&ignore=.csv", stringsAsFactors=F)

However, when I incorporate using a variable for the ticker, it no longer works.  

SymA<- "SPY"
Sym1<- cat('http://ichart.finance.yahoo.com/table.csv?s=",SymA,"&ignore=.csv",sep="";)
Symbol<- read.csv(Sym1, stringsAsFactors=F)

I know that the problem lies in the concatenation, but I've tried different variations of cat() and toString() (and others) with SymA and Sym1 but cannot seem to get a string together that will work.  Would appreciate any suggestions for this simple problem?? 

Thank you.