Can the x-axis labels be ordered when using a combined bar & line graph in R?

Question

Using the variables (day, month, count) in the data frame d, I use ggplot below:

day <- c("Mon","Tues","Wed","Thurs","Fri","Sat","Sun","Week","Mon","Tues","Wed","Thurs","Fri","Sat","Sun","Week")
day <- factor(day, level=c("Mon","Tues","Wed","Thurs","Fri","Sat","Sun","Week"))
month<-c("Jan","Jan","Jan","Jan","Jan","Jan","Jan","Jan","Feb","Feb","Feb","Feb","Feb","Feb","Feb","Feb")
month<-factor(month,level=c("Jan","Feb"))
count <- c(4,5,6,8,3,4,9,5.57,2,4,3,7,1,9,3,4.14)
d <- data.frame(day=day,count=count,month=month)
d

The line graph below correctly orders the days:

ggplot()+geom_line(data=d[d$day!="Week",],aes(x=day, y=count, group=month, colour=month))

The bar graph below correctly displays the two counts:

ggplot()+geom_bar(data=d[d$day=="Week",],aes(x=day, y=count, fill=month),position="dodge")

However, the order of days is incorrect in the combined graph:

ggplot()+geom_line(data=d[d$day!="Week",],aes(x=day, y=count, group=month, colour=month))+geom_bar(data=d[d$day=="Week",],aes(x=day, y=count, fill=month),position="dodge") 

How can I correctly display the order of days on the x-axis?

Answer 1

You can use scale_x_discrete() to change order of breaks with argument limits=. As in your original data frame factor levels are in right order then you can just use limits=levels(d$day).

ggplot()+
  geom_line(data=d[d$day!="Week",],
                  aes(x=day, y=count, group=month, colour=month))+
  geom_bar(data=d[d$day=="Week",],
                  aes(x=day, y=count, fill=month),position="dodge")+
  scale_x_discrete(limits=levels(d$day))