Plot how much today's close is different from the close 24 days ago in % terms

blueberry.r

blueberry <- function(sym="SLV", file="~/Desktop/24_days_ago.png"){
	
	require("quantmod")

	ticker <- getSymbols(sym, auto.assign=FALSE)

	ticker <- merge(ticker[,4], lag(ticker[,4],24))

	ticker <- na.locf(ticker, na.rm=TRUE)

	lag_diff <- function(x,y){

		pdiff <- (x - y)/y
		return(pdiff)
	}

	ticker <- cbind(ticker, apply(ticker,1, function(x)lag_diff(x[1],x[2])))

	change <- ticker[,3]

	png(file)

	# plot(change,          main="% Change From Close Today & Close 24 Days Ago")
	# hist(change,          main="% Change From Close Today & Close 24 Days Ago")
	plot(density(change), main="% Change From Close Today & Close 24 Days Ago")
	polygon(density(change), col="blue") 
		
	dev.off()

}