Ordering Data with Stacked Bar Charts in ggplot2

Question

Alternate title: replacing a continuous legend with a discrete legend in ggplot2

I'm trying to create a stacked bar chart using this code:

DataTest = data.frame(Order = 1:7,
                  Data = c(340, 464, 93, 218, 16, 206, 103),
                  Category = factor(c("Free", "Unavailable", "Free",
                                    "Unavailable", "Free", "Unavailable", "Free"),
                                    levels = c("Free", "Unavailable")))

ggplot(DataTest, aes(x="Thing", y=Data, fill=Category)) +
  geom_bar(position="stack", stat="identity")

Ignore x, it's unimportant. The plotted graph looks like this:

Stacked bar chart with 2 blocks of solid colour

The problem is, I want the data to be ordered like the rows in my data frame, so the stacked bar chart should be striped with alternating colours, like this:

Stacked bar chart striped with alternating colours, but with a continuous legend instead of a discrete legend

In fact, this bar chart is exactly what I want - aside from the legend. I want the legend to show just two colours, but I can't figure out how to set that up.

The code for this bar chart is:

DataTest[["Category"]] = c(1, 0, 1, 0, 1, 0, 1) # change Category from a factor to numeric
ggplot(DataTest, aes(x="Thing", y=Data, fill=Category)) +
  geom_bar(position="stack", stat="identity")

The same as the previous snippet, but this time Catgeory is a numeric vector of only 1s and 0s. If I use a logical vector instead of numeric, once again the bars are grouped by colour.

Here's one last thing I tried:

ggplot(DataTest, aes(x="Thing", y=Data, fill=Order, colour=Category)) +
  geom_bar(position="stack", stat="identity")

Messy bar chart that has some order but is nevertheless grouped by Category

Which shows that despite stat="identity", ggplot is insisting on sorting the data.

SO.

To be clear, I can't figure out how to sort my data by Order, but colour my data according to Category - except by introducing a continuous legend, which I don't want.

Answer 1

Not really sure that I understand your question. Wild stab at the dark here:

DataTest$gp <- seq(nrow(DataTest))

ggplot(DataTest, aes(x="thing", y=Data, fill=Category, group=factor(gp))) + 
      geom_bar(stat="identity")