How to order bars in barplot in ggplot?

Question

[anamaria]

Hi,

I have a barplot like this:

I created it with this code:

toplot.N <- data.frame( set=c("FLCN", "All SNPs", "eQTL from 103 genes","All eQTL"),
                    FDR =c(FDR1FI,FDR2FI,FDR3FI,FDR4FI))

p<-ggplot(toplot.N, aes(x=set, y=FDR, fill=set)) + labs(y = "pi_1")+
   geom_bar(stat="identity")+theme(axis.title.x = element_blank())+
  geom_hline(yintercept=0.05, linetype="dashed", color = "red")
p

How would I change this so that the order of bars is: "All SNPs","All eQTL","eQTL from 103 genes","FLCN"

Thanks Ana

Answer 1

[zx8754]

We could change order of factor levels before plotting:

toplot.N$set <- factor(toplot.N$set,
                       levels = c("All SNPs", "All eQTL", "eQTL from 103 genes", "FLCN"))

[anamaria]

This is great, thank you so much!

Answer 2

[grant.hovhannisyan]

Try to research before asking, see https://stackoverflow.com/questions/5208679/order-bars-in-ggplot2-bar-graph

library(ggplot2)
toplot.N <- data.frame( set=c("FLCN", "All SNPs", "eQTL from 103 genes","All eQTL"),
                        FDR =c(10,20,30,40))

positions <- c( "All SNPs","All eQTL","eQTL from 103 genes","FLCN")

p<-ggplot(toplot.N, aes(x=set, y=FDR, fill=set)) + labs(y = "pi_1")+
  geom_bar(stat="identity")+theme(axis.title.x = element_blank())+
  geom_hline(yintercept=0.05, linetype="dashed", color = "red") + 
  scale_x_discrete(limits = positions)
p

[anamaria]

any idea how I would implement that from stackoverlow in my case?