When trying to replace values, “missing values are not allowed in subscripted assignments of data frames”

Question

I have a table that has two columns: whether you were sick (H01) and the number of days sick (H03). However, the number of days sick is NA if H01 == false, and I would like to s

Answer 1

Simply use the subset() function to exclude all NA from the string.

It works as x[subset & !is.na(subset)]. Look at this data:

> x <- data.frame(a = c(T,F,T,F,NA,F,T, F, NA,NA,T,T,F),
>                 b = c(F,T,T,F,T, T,NA,NA,F, T, T,F,F))

Subsetting with [ operator returns this:

> x[x$b == T & x$a == F, ]

         a    b
2    FALSE TRUE
NA      NA   NA
6    FALSE TRUE
NA.1    NA   NA
NA.2    NA   NA

And subset() does what we want:

> subset(x, b == T & a == F)

      a    b
2 FALSE TRUE
6 FALSE TRUE

To change the values of subsetted variables:

> ss <- subset(x, b == T & a == F)
> x[rownames(ss), 'a'] <- T

> x[c(2,6), ]

     a    b
2 TRUE TRUE
6 TRUE TRUE