Error in If else loop in R - r

Question

I am writing one code in R. First I am creating one blank column in the data set and I want to assign 0 and 1 value in that column according to some conditions. Here is my code
#Creating a empty column in the data file
Mydata$final <- "";
#To assign 0,1 value in final variable
if(Mydata$Default_Config == "No" & is.na(Mydata$Best_Config)=="TRUE" & (Mydata$AlmostDefaultConfig!=1 | Mydata$AlmostDefaultConfig!=3)){
Mydata$final <- 1
}else{
Mydata$final <- 0
}
And I am getting this error
Warning message:
In if (Mydata$Default_Config == "No" & is.na(Mydata$Best_Config) == :
the condition has length > 1 and only the first element will be used
How Can I fix this error? Please help me out. Thanks in advance

Answer 1

Your problem is one of vectorisation. if is not vectorised. You are testing multiple values in each comparison in your if statement and R is telling you it will only use the first because if is not vectorised. You need ifelse which is vectorised:
ifelse( Mydata$Default_Config == "No" & is.na(Mydata$Best_Config)=="TRUE" & (Mydata$AlmostDefaultConfig!=1 | Mydata$AlmostDefaultConfig!=3) , 1 , 0 )
A reproducible example is below. If x is > 5 and y is even then return 1 otherwise return 0:
x <- 1:10
# [1] 1 2 3 4 5 6 7 8 9 10
y <- seq(1,30,3)
# [1] 1 4 7 10 13 16 19 22 25 28
x > 5
# [1] FALSE FALSE FALSE FALSE FALSE TRUE TRUE TRUE TRUE TRUE
y %% 2 == 0
# [1] FALSE TRUE FALSE TRUE FALSE TRUE FALSE TRUE FALSE TRUE
ifelse( x > 5 & y %% 2 == 0 , 1 , 0 )
# [1] 0 0 0 0 0 1 0 1 0 1

Answer 2

An alternative approach is to take advantage of R's coercion. You have a set of conditionals which are vectorizable, and R is happy to convert TRUE/FALSE to 1 / 0, so you can write it like:
Mydata$final <- ( (Mydata$Default_Config == "No") *( is.na(Mydata$Best_Config)=="TRUE") * (Mydata$AlmostDefaultConfig!=1 + Mydata$AlmostDefaultConfig!=3)) )
(extra parentheses added for clarity) .
Apologies if I fouled up the logic there.
Edit: My code for the OR won't quite work, since if both sides are TRUE you'd get a big number ("2" :-) ). Change it to as.logical((Mydata$AlmostDefaultConfig!=1 + Mydata$AlmostDefaultConfig!=3))