[R] Multi-word column names in a data frame

[philipsm m@ili@g off cp@@el1@stormweb@@et]

I am having trouble working with column names in a data frame. My  
column names are multi-word text strings and I like it that way. I  
want to loop through the columns, plotting graphs for each one, and I  
want to use the column names in the chart labels and in the file names  
when I save the charts. Here is a simple reproducible example that  
does not work.

library(dplyr)
`RefDate` <- as.Date(c("2010-11-1","2010-12-01","2011-01-01"))
`Number of vegetables` <- c(14,23,45)
`Number of people` <- c(20,30,40)
MyData <- data.frame(RefDate,`Number of vegetables`,`Number of  
people`,check.names=FALSE)
MyVars <- c("Number of vegetables","Number of people")
for (A in MyVars) {
   g2 <- ggplot(MyData,aes(RefDate,eval(parse(text=A)))) + geom_line() +
     labs(title = paste(A," adjusted",sep=""))
   g2
   ggsave(paste(A,".jpg",sep=""),g2,height=5,width=8,dpi=300)
}

Philip