根据 R 中其他列中的值和条件计算新列

Question

I have a csv table like this loaded in R.

method	SOC	SOC2
WB	1.5
Com	2.5
LOI	3.1

I want to calculate column "SOC2" with conditions from method column like as follows: If the method in the method column is WB, multiply SOC by 10 and put it in SOC2 column. If the method in the method column is Com, multiply SOC by 20 and put it in SOC2 column. if the method in the method column is LOI, multiply SOC by 30 and out ut ub SOC2 Column.

How can I do that in R please?

Answer 1

Try this:

library(dplyr)

df <- data.frame(method = c("WB", "Com", "LOI"), SOC = c(1.5, 2.5, 3.1))

df %>% mutate(SOC2 = case_when(
  method == "WB" ~ SOC * 10, 
  method == "Com" ~ SOC * 20, 
  method == "LOI" ~ SOC * 30
))

  method SOC SOC2
1     WB 1.5   15
2    Com 2.5   50
3    LOI 3.1   93

Answer 2

You can do it like this:

wbIndices <- df$method == "WB"
ComIndices <- df$method == "Com"
LOIIndices <- df$method == "LOI"

df$SOC2 <- df$SOC[wbIndices]*10
df$SOC2 <- df$SOC[ComIndices]*20
df$SOC2 <- df$SOC[LOIIndices]*30