R: merge copies of the same variable

Question

I have data similar to this in R:

subjID = c(1,2,3,4) var1 = c(3,8,NA,6) var1.copy = c(NA,NA,5,NA) fake = data.frame(subjID = subjID, var1 = var1, var1 = var1.copy) 

which is as follows:

 > fake subjID var1 var1.1 1 1 3 NA 2 2 8 NA 3 3 NA 5 4 4 6 NA 

Var1 and Var1.1 represent the same variable, so each object has an NA for one column and a numerical value in the other (who does not have two NA or two numbers). I want to combine the columns to get one Var1: (3, 8, 5, 6).

Any tips on how to do this?

Answer 1

You can use is.na, which can be vectorized as:

 # get all the ones we can from var1 var.merged = var1; # which ones are available in var1.copy but not in var1? ind = is.na(var1) & !is.na(var1.copy); # use those to fill in the blanks var.merged[ind] = var1.copy[ind]; 

Answer 2

If you are dealing with only two columns, and there are never two numbers or two NA, you can calculate the average value of the row and ignore the missing values:

 fake$fixed <- rowMeans(fake[, c("var1", "var1.1")], na.rm=TRUE) 

Answer 3

It depends on how you want to come together if there are conflicts.

You can simply put all non-NA values ​​in var.1.1 into the corresponding var1 interval. In case of conflict, this will contribute to var.1.1 .

 var1[!is.na(var1.copy)] <- var1.copy[!is.na(var1.copy)] 

You can simply populate all the NA values ​​in var1 with the corresponding var1.1 values. In case of conflict, this will contribute to var1 .

 var1[is.na(var1)] <- var1.copy[is.na(var1)]