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

Question

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!

Answer 1

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