在 R 数据框中，对于给定的行，如何找到 A 列中的值与 B 列中的值的百分比？

Question

Say I have a data frame as follows:

dataDF <- data.frame(
   cola = c(10, 15, 30),
   colb = c(100, 300, 800)
   )


   cola   colb
1  10     100
2  15     300
3  30     800

How can I find what percent column a row 1 (10) is of column b row 1 (100), and so on for rows 2 and 3?

Thanks.

Answer 1

One option is prop.table and specify the margin . Here it is by row, so we use 1 and if it is column, it would be 2

prop.table(as.matrix(dataDF), 1)

Answer 2

Another way which is useful if you want to have a column containing the percentages is this:

library(dplyr)

dataDF <- data.frame(
  cola = c(10, 15, 30),
  colb = c(100, 300, 800)
)
dataDF2 <- mutate(dataDF, colc = cola/colb*100)
dataDF2
  cola colb  colc
1   10  100 10.00
2   15  300  5.00
3   30  800  3.75

Answer 3

Another solution with data.table package :

library(data.table)
setDT(dataDF)[, colc := cola/colb*100]

> dataDT
   cola colb  colc
1:   10  100 10.00
2:   15  300  5.00
3:   30  800  3.75