如何根据r中多个列的值创建变量

Question

I have a data frame that has three variables with the valid values of 1,2,3,4,5,6,7 for each variable. If there isn't a numeric value assigned to the variable, it will show NA . The data frame a looks like below:

   ak_eth co_eth pa_eth
1     NA      1     NA
2     NA     NA      1
3     NA     NA     NA
4      2     NA     NA
5     NA     NA      4
6     NA     NA     NA

Each row could have NA across all three variables or have only one value in one of the three variables. I want to create a new variable called recode that takes values from the existing three variables. If all three existing variables are NA , the new value is NA ; if one of the three existing variables has a value, then take that value for the new variable. I've tried this, but it seems didn't work for me.

a$recode[is.na(a$ak_eth) & is.na(a$co_eth) & is.na(a$pa_eth)] <- "NA"
library(car)
a$recode <- recode(a$ak_eth, "1=1;2=2;3=3;4=4;5=5;6=6;7=7")
a$recode <- recode(a$co_eth, "1=1;2=2;3=3;4=4;5=5;6=6;7=7")
a$recode <- recode(a$pa_eth, "1=1;2=2;3=3;4=4;5=5;6=6;7=7")

Any suggestions will be appreciated. Thanks!

Answer 1

We can use pmax

a$Recode_Var <-  do.call(pmax, c(a, na.rm = TRUE))

Or use pmin

a$Recode_Var <- do.call(pmin, c(a, na.rm = TRUE))

---

Or another option is rowSums

r1 <- rowSums(a, na.rm = TRUE)
a$Recode_Var <- replace(r1, r1==0, NA)

NOTE: According to the OP's post Each row could have NA across all three variables or have only one value in one of the three variables