Calculating percentage for each value in multiply columns. based on maximum value in each column usi-CodePudding

I am trying to form a loop where it takes the maximum value from each column, then use it to calculate the percentage for the other values within each column. Someone asked a similar question in the past before, however the solution given was calculating the percentages the opposite way round to what I need.

My df:

a	b	c	d
1115.68	67.52	151.13	183.32
1083.16	53.75	136.70	202.56
1076.69	56.07	157.77	196.43

Desire output:

a	b	c	d
100.00	100.00	95.79	90.50
97.09	79.61	86.65	100.00
96.51	83.05	100.00	96.97

Current output, I am getting the percentages in the opposite way round:

a	b	c	d
100.00	6.05	13.55	16.43
100.00	4.96	12.62	18.70
100.00	5.21	14.65	18.24

The code I was using is this:

output <- df
for (i in 1:nrow(df)) {
  highvalue <- max(df[i, 1:4])
  for (j in 1:4) {
    output[i, j] <- df[i, j] * 100/highvalue
  }
}
output

What is wrong with the code?

CodePudding user response：

You find maximum in row, not in column. Loop version:

output <- df
for (i in 1:ncol(df)) {
  highvalue <- max(df[, i])
  output[, i] <- output[, i] / highvalue * 100
}

But You can use good version of code:

library(dplyr)
output <- df / df %>% lapply(max) * 100