MYaseen208 - 1 year ago 141

R Question

I'd like to show data values on stacked bar chart in ggplot2. Here is my attempted code

`Year <- c(rep(c("2006-07", "2007-08", "2008-09", "2009-10"), each = 4))`

Category <- c(rep(c("A", "B", "C", "D"), times = 4))

Frequency <- c(168, 259, 226, 340, 216, 431, 319, 368, 423, 645, 234, 685, 166, 467, 274, 251)

Data <- data.frame(Year, Category, Frequency)

library(ggplot2)

p <- qplot(Year, Frequency, data = Data, geom = "bar", fill = Category, theme_set(theme_bw()))

p + geom_text(aes(label = Frequency), size = 3, hjust = 0.5, vjust = 3, position = "stack")

I'd like to show these data values in the middle of each portion. Any help in this regard will be highly appreciated. Thanks

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Answer Source

Here is one approach, which calculates the midpoints of the bars.

```
library(ggplot2)
library(plyr)
# calculate midpoints of bars (simplified using comment by @DWin)
Data <- ddply(Data, .(Year),
transform, pos = cumsum(Frequency) - (0.5 * Frequency)
)
# library(dplyr) ## If using dplyr...
# Data <- group_by(Data,Year) %>%
# mutate(pos = cumsum(Frequency) - (0.5 * Frequency))
# plot bars and add text
p <- ggplot(Data, aes(x = Year, y = Frequency)) +
geom_bar(aes(fill = Category), stat="identity") +
geom_text(aes(label = Frequency, y = pos), size = 3)
```