How to Order a geom_bar plot in r by a third category

Question

I have a dataframe with 3 categories and I want to make a bar plot with count on the Y axis and seq on the x-axis, but ordered by depth (which goes much higher than 2) but I cannot figure out how to do it.

s <- df
head(s)
     count     depth   seq
1     10         1      A
2     20         2      AA
3     30         1      TT
4     25         3      C
5     40         2      AAA
6     12         2      G

This is my feeble attempt:

ggplot(data = s, aes(x=as.factor(s$seq), y=count, color = depth)) + 
   geom_bar(stat="identity") 

It goes without saying but I'm not very good at coding.

Thanks

Answer 1

We can use the reorder() function within the aes() ie

> ggplot(data = s, aes(x=reorder(as.factor(seq), -depth), y=count, fill = depth)) + 
     geom_bar(stat = 'identity') 

Data:

> dput(s)
structure(list(count = c(10, 20, 30, 25, 40, 12), depth = c(1, 
2, 1, 3, 2, 2), seq = structure(c(1L, 2L, 6L, 4L, 3L, 5L), .Label = c("A", 
"AA", "AAA", "C", "G", "TT"), class = "factor")), .Names = c("count", 
"depth", "seq"), row.names = c(NA, -6L), class = "data.frame")