Loop over string variables in R

Question

When programming in Stata I often find myself using the loop index in the programming. For example, I\'ll loop over a list of the variables nominalprice and realprice:

Answer 1

Using ggplot2 and reshape:

library(ggplot2)
library(reshape)
df <- data.frame(nominalprice=rexp(10), time=1:10)
df <- transform(df, realprice=nominalprice*runif(10,.9,1.1))
dfm <- melt(df, id.var=c("time"))
qplot(time, value, facets=~variable, data=dfm)