How to divide a number of columns by one column?

Question

I have the below dataset:

Monday Tuesday Wednesday Friday Saturday Total
2       3      4          5      6        20
3       6      7          5      1        22

I am doing the below:

I need to divide first row: 2/20, 3/20, 4/20, 5/20, 6/20

And on the second row: 3/22, 6/22, 7/22, 5/22, 1/22.

I can do this by extracting the columns but it is long and tedious, there must be an easier way.

Answer 1

You can simply do

df[,1:5] / df[,6] 

Answer 2

You can use dlyr to operate rowwise on multiple columns:

library(tidyverse)
library(margrittr)

df <- data.frame(
  Monday=c(2,3), 
  Tuesday=c(3,6), 
  Wednesday=c(4,7),
  Friday=c(5,5),
  Saturday=c(6,1),
  Total=c(20,22))

df %>%
  mutate(
    across(c(1:5),
           .fns = ~./Total))

This then returns:

     Monday   Tuesday Wednesday    Friday   Saturday Total
1 0.1000000 0.1500000 0.2000000 0.2500000 0.30000000    20
2 0.1363636 0.2727273 0.3181818 0.2272727 0.04545455    22