Assigning NAs into a dataframe in R - r

Question

I have been trying to assign NAs by using for loop, but is not working and I know there are possible easiest ways to do this.
I want to create an extra column (just like the column in the example named Desire_Output) in which I will assign NA to any row that in the Value column has a number higher than 1. Also, I want to assign NAs to the next following two rows. If there are NAs in the Value column, just also put NAs in the desire output column.
Here is the example:
Event<- c(1,2,2,2,2,2,2,3,3,4,4,4,4,4,5,6,6,6,7)
Value<- c(5,3,0,0,0,2,0,1,10,0,0,NA,NA,NA,1,0,8,0,0)
Desire_output<- c(NA,NA,NA,NA,0,NA,NA,NA,NA,NA,NA,NA,NA,NA,1,0,NA,NA,NA)
A<- data.frame(Event,Value,Desire_output)
Event Value Desire_output
1 1 5 NA
2 2 3 NA
3 2 0 NA
4 2 0 NA
5 2 0 0
6 2 2 NA
7 2 0 NA
8 3 1 NA
9 3 10 NA
10 4 0 NA
11 4 0 NA
12 4 NA NA
13 4 NA NA
14 4 NA NA
15 5 1 1
16 6 0 0
17 6 8 NA
18 6 0 NA
19 7 0 NA
This is what I tried to do, but when I getvto the NAs in the Value column I started to have some troubles.
for (f in 1:(nrow(A)-1)){
if(A$Value2[f] > 1){
A$Value2[f]<- NA
A$Value2[f+1]<- NA
A$Value[f+2]<- NA
}else{
}
}
Please let me know if you have an easiest way to do it with any other method.

Answer 1

We can first copy Value column to Desired_output column and find out the indices (inds) where Value is greater than 1 and add NA to that row and next two rows as well.
A$Desired_output <- A$Value
inds <- which(A$Value > 1)
A$Desired_output[unique(c(inds, inds + 1, inds + 2))] <- NA
A
# Event Value Desired_output
#1 1 5 NA
#2 2 3 NA
#3 2 0 NA
#4 2 0 NA
#5 2 0 0
#6 2 2 NA
#7 2 0 NA
#8 3 1 NA
#9 3 10 NA
#10 4 0 NA
#11 4 0 NA
#12 4 NA NA
#13 4 NA NA
#14 4 NA NA
#15 5 1 1
#16 6 0 0
#17 6 8 NA
#18 6 0 NA
#19 7 0 NA

Answer 2

You might use the ifelse. In the below code I have used the OR statement inside the ifelse code.
A$Desire_output<- ifelse(A$Value>1 | is.na(A$Value), NA, A$Value)
I hope this will help.

Answer 3

I think this gives what you're after, but other solutions may be less laborious.
Event<- c(1,2,2,2,2,2,2,3,3,4,4,4,4,4,5,6,6,6,7)
Value<- c(5,3,0,0,0,2,0,1,10,0,0,NA,NA,NA,1,0,8,0,0)
A<- data.frame(Event,Value,Desired_output)
A["Desired_Output"] <- 0
for(i in seq(length(A$Value))){
if(!is.na(A$Desired_Output[i])){
if(A$Value[i] > 1 & !is.na(A$Value[i])){
A$Desired_Output[c(i, i+1, i+2)] <- NA
}else if(is.na(A$Value[i])){
A$Desired_Output[i] <- NA
}else{
A$Desired_Output[i] <- A$Value[i]
}
}
}