Sort data day-wise

Is there a way to sort data day-wise instead of by the increasing/decreasing order of values? The data is basically as below.

Day n
Friday 12
Monday 25
Saturday 18
Sunday 14

Below is the graph for the data plot. I want it to appear in the order Monday-Sunday.

Please help.

You need to make your Day column a factor with the levels set in the order that you want them on the x axis. Here is an example with just four days.

library(ggplot2)

DF <- data.frame(Day = c("Friday", "Monday", "Sunday", "Saturday"),
                 n = c(23,18,28,21))

DF$Day <-  factor(DF$Day, levels = c("Monday", "Friday", "Saturday", "Sunday"))

ggplot(DF, aes(Day, n)) + geom_col(fill = "steelblue")