rdataframerecode

How to make all values in a row after a specific value appears, NA in R


I have data in R that looks like this:

T1 <- c(0,0,0,0,0)
T2 <- c(1,0,0,0,0)
T3 <- c(0,1,0,0,0)
T4 <- c(1,1,0,NA,1)
T5 <- c(0,1,0,NA,0)
df <- data.frame(T1,T2,T3,T4,T5)

  T1 T2 T3 T4 T5
1  0  1  0  1  0
2  0  0  1  1  1
3  0  0  0  0  0
4  0  0  0 NA NA
5  0  0  0  1  0

What I am hoping to do is to turn every value after the 1st "1" appears into NA. So it would look something like this:

  T1 T2 T3 T4 T5
1  0  1 NA NA NA
2  0  0  1 NA NA
3  0  0  0  0  0
4  0  0  0 NA NA
5  0  0  0  1 NA

Any suggestions? Thank you!


Solution

  • Using apply from base R Get the first 1 with which.max

    first1 = which.max(x == 1)

    Generate an integer that can be sequenced and subset the values that are not within the sequence. mySeq <-ifelse(first1 == 1, length(x), first1)

    Subsetted values are given NA

    x[-seq(mySeq)] <- NA

    return values

    df[] <- t(apply(df, 1, \(x) {
      first1 = which.max(x == 1)
      mySeq <-ifelse(first1 == 1, length(x), first1)
      x[-seq(mySeq)] <- NA
      x
      }))
    
      T1 T2 T3 T4 T5
    1  0  1 NA NA NA
    2  0  0  1 NA NA
    3  0  0  0  0  0
    4  0  0  0 NA NA
    5  0  0  0  1 NA