改变堆叠区域的顺序

Question

I am trying to order the stacked geom_area in an arbitrary way.

For instance:

investments <- data.frame(Date = c(as.Date('2019-01-01'), as.Date('2019-01-01'),
                                   as.Date('2019-01-01'), as.Date('2019-01-02'),
                                   as.Date('2019-01-02'), as.Date('2019-01-02')),
                          Amount = c(100, 200, 150, 120, 200, 130),
                          InvestType = c("Shares", "Cash", "Bonds", 
                                         "Shares", "Cash", "Bonds"))

ggplot()+
  geom_area(data = investments,
            aes(x = Date, y = Amount, fill = InvestType))

This gives the above graph with the stacked areas ordered "Shares, Cash, Bonds". Now I want "Cash" to always be on top.

I tried sorting the dataframe with:

investments  <- arrange(investments, 
                        factor(InvestType, levels = c("Shares", "Bonds", "Cash")))

This sorted the data frame by InvestType but did not change the order of the stacked areas.

Answer 1

@Z.Lin gave the correct answer in the comments. I needed the stacked area variable to be a factor and have the levels set in the right order. Converted using investments$InvestType <- factor(investments$InvestType, levels = c("Shares", "Bonds", "Cash")) before plotting as per the comment.