Consider the following row in a dataset:-
#Row (initially):
NA NA NA NA NA NA NA 2 3 1 4 5 2 NA NA 6 7
I want all such rows to be transformed into
#Row (modified) :
0 0 0 0 0 0 0 2 3 1 4 5 2 NA NA 6 7
Only the initial NA that occur before any non na value shout be replaced by zero and not those that come afterwards.
Edit: My data is matrix, example:
NA NA NA NA 1 1 1 1 1 1
NA NA NA NA 1 1 1 1 1 1
NA NA NA NA 1 1 1 1 1 1
NA NA NA NA NA NA NA 1 NA 1
NA NA NA NA NA NA NA 1 NA 1
NA NA NA NA NA NA NA NA NA 1
1 1 1 1 1 1 1 1 NA 1
1 1 1 1 1 1 1 1 1 1
It should be modified to
0 0 0 0 1 1 1 1 1 1
0 0 0 0 1 1 1 1 1 1
0 0 0 0 1 1 1 1 1 1
0 0 0 0 0 0 0 1 NA 1
0 0 0 0 0 0 0 1 NA 1
0 0 0 0 0 0 0 0 0 1
1 1 1 1 1 1 1 1 NA 1
1 1 1 1 1 1 1 1 1 1
Define a function and use apply(). Here a working example. The function is just testing if the cumsum of logical values is increasing.
x <- c(NA, NA, NA, NA, 1, 0, NA, NA, 3)
y <- c(2, NA, 3, NA, 1, 0, NA, 2, 3)
z <- c(NA, NA, 3, NA, 1, 0, NA, NA, 3)
df <- data.frame(x, y, z)
initialNA <- function(x) {
index <- cumsum(is.na(x)) >= seq_along(x)
x[index] <- 0
x
}
df2 <- data.frame(t(apply(df, 1, initialNA)))