r - ggplot2: sorting a plot

Question

I have a data.frame, that is sorted from highest to lowest. For example:

x <- structure(list(variable = structure(c(10L, 6L, 3L, 4L, 2L, 8L, 
9L, 5L, 1L, 7L), .Label = c("a", "b", "c", "d", "e", "f", "g", 
"h", "i", "j"), class = c("ordered", "factor")), value = c(0.990683229813665, 
0.975155279503106, 0.928571428571429, 0.807453416149068, 0.717391304347826, 
0.388198757763975, 0.357142857142857, 0.201863354037267, 0.173913043478261, 
0.0496894409937888)), .Names = c("variable", "value"), row.names = c(10L, 
6L, 3L, 4L, 2L, 8L, 9L, 5L, 1L, 7L), class = "data.frame")

ggplot(x, aes(x=variable,y=value)) + geom_bar(stat="identity") + 
 scale_y_continuous("",label=scales::percent) + coord_flip() 

Now, the data is nice and sorted, but when I plot, it comes out sorted by factor. It's annoying, how do I fix it?

Answer 1

This seems to be what you're looking for:

g <- ggplot(x, aes(reorder(variable, value), value))
g + geom_bar() + scale_y_continuous(formatter="percent") + coord_flip()

The reorder() function will reorder your x axis items according to the value of variable.