How to color bar plot with bars dependent on column names in R

0
votes

I have two data frames and a function maxthree which takes in a data frame and row name as an argument and plots the three highest value on the row (in a descending order) and the name of the column of three highest value.


    set.seed(0)
    df <- data.frame(A=c(3,2,1,4,5),B=c(1,6,3,8,4),C=c(2,1,4,8,9), D=c(4,1,2,4,6))
    row.names(df)<-c("R1","R2","R3","R4","R5")

    df2 <- data.frame(E=c(2,5,6,1,4),F=c(2,4,2,5,1),G=c(5,6,2,7,3),H=c(8,2,7,4,1))
    row.names(df2)<-c("R6","R7","R8","R9","R10")

    print(df)

       A B C D
    R1 3 1 2 4
    R2 2 6 1 1
    R3 1 3 4 2
    R4 4 8 8 4
    R5 5 4 9 6

    print(df2)

        E F G H
    R6  2 2 5 8
    R7  5 4 6 2
    R8  6 2 2 7
    R9  1 5 7 4
    R10 4 1 3 1

    maxthree <- function(data, row) {
      order<-as.matrix(data[row, order(unlist(data[row, ]), decreasing = TRUE)[1:3]])
      barplot(order)
    }


    maxthree(df2, "R7")

enter image description here

I am trying to have the function maxthree to color each bar differently depending on the column they would be on. So, for example, if columns in df2 would be colored in a following way: E=green, F=red, G=yellow, H=blue, the bars in the previous bar graph should be yellow, green, red (in that order). I know how to color in a normal bar plot by using "col" inside barplot() but I don't know how to color in the bars in this situation since it is dependent on which columns appear on the bar plot and on the order of them.

1
rfunctiondataframebar-chart

1 Answers

1
votes

Here's an approach with a named vector defining colors for different rows:

col.colors <- c(E="green", F="red", G="yellow", H="blue")

maxthree <- function(data, row) {
      order<-as.matrix(data[row, order(unlist(data[row, ]), decreasing = TRUE)[1:3]])
      order.names <- colnames(order)
      order.colors <- col.colors[order.names]
      barplot(as.vector(order), names.arg = order.names, col = order.colors)
}
maxthree(df2, "R7")

enter image description here