I wrote the following function:
# This method gets historical stock data for the stock Avalon Bay whose
symbol is AVB.
getReturns <- function(norm = FALSE)
{
library(quantmod)
getSymbols("AVB", src = "yahoo", from = start, to = end)
length = length( AVB$AVB.Close )
close = as.numeric( AVB$AVB.Close )
cat( "length = ", length(close ), "\n" )
for( i in 1:length-1 )
diff[i] = ((close[i+1] - close[i]) ) / close[i]
u = mean(diff)
stdDev = sd(diff)
cat( "stdDev = ", stdDev, "\n" )
if ( norm == TRUE ) {
diff = (diff - u)
diff = diff / stdDev
}
return (diff)
}
I would like to generalize it to work for any stock by passing in the
stock symbol. So the header for the
function would be:
getReturns <- function(symbol, norm = FALSE)
Now how do I update this line:
length = length( AVB$AVB.Close )
This statement will not work:
length = length( symbol$AVB.Close )
because the name that holds the closing price is a function of the stock
symbol.
Thanks,
Bob
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