CODEWITHSUNDEEP
r
A. Hada
A. Hada

Reputation: 105

How to replace NAs in the middle and the left side of each row in a data frame with a value?

I have a data frame that has NA's in every row. Some are on the left, some in the middle, and some on the right. Something like this:

a <- c(NA, NA, 1, NA)
b <- c(NA, 1,  1, NA)
c <- c(NA, NA, 1, 1)
d <- c(1, 1, NA, 1)
df <- data.frame(a, b, c, d)
df
# a  b  c  d
# NA NA NA 1
# NA 1  NA 1
# 1  1  1  NA
# NA NA 1  1

I would like to replace all the NAs that are in the middle and on the right side with 0 but keep all the NA's leading to a 1 on the left as NA. So I would like an efficient way (my data frame is large) to have this data frame:

# a  b  c  d
# NA NA NA 1
# NA 1  0  1
# 1  1  1  0
# NA NA 1  1

Upvotes: 1

Views: 37

Answers (1)

akrun
akrun

Reputation: 887531

We can use apply to loop over the rows, find the index of the first occurence of 1. Then replace the NAs from that element to the last with 0

df[] <- t(apply(df, 1, function(x) {
               i1 <- which(x == 1)[1]
               i2 <- i1:length(x)
               x[i2][is.na(x[i2])] <- 0
               x}))

Or another option is

df[] <-  t(apply(df, 1, function(x) replace(x, 
                 cumsum(x ==1 & !is.na(x)) >= 1 & is.na(x), 0)))

Upvotes: 1

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