根据 R 中数据框中的其他列创建新列

Question

I have a data frame with three columns and four rows. I want to create a new column based on available columns such that new column gets the maximum value of the corresponding row (no matter if there is NA or not). If all are NAs, the new column gets NA. enter image description here

Thanks.

Answer 1

We could use pmax with na.rm specified as TRUE (assuming it is a data.frame object and the missing values are NA )

df1$new_column <- do.call(pmax, c(df1, na.rm = TRUE))

-output

> df1
   A   B   C new_column
1 98  NA  NA         98
2 NA  NA  NA         NA
3 98 100  NA        100
4 98 100 200        200

data

df1 <- data.frame(A = c(98, NA, 98, 98), B = c(NA, NA, 100, 100),
    C = c(NA, NA, NA, 200))