filter not retaining rows with NA values

[gtumuluri]

Filter is removing rows with NA values on inequality condition. While it is not hard to add to the condition to keep those rows, it does mean you almost always have to write explicit code as absence of NA can't be assured.

mydf <- data.frame(x = 1:5, y = c(letters[1:3], rep(NA, 2)))
mydf
  x    y
1 1    a
2 2    b
3 3    c
4 4 <NA>
5 5 <NA>

filter(mydf, y != 'a')
  x y
1 2 b
2 3 c

packageVersion('dplyr')
[1] ‘0.7.2’

[batpigandme]

Hi,
So, from what I understand, this is by design/due to the way R deals with NAs which I can't describe any better than Hadley and Garrett do in the Missing values sub-section of Filter Rows with filter() in r4ds 😬!

Ultimately, as you described as well:

filter() only includes rows where the condition is TRUE; it excludes both FALSE and NA values. If you want to preserve missing values, ask for them explicitly...

Hopefully this helps clarify a bit!

[gtumuluri]

At least an option like keep.na = TRUE or something can be added with default value of FALSE?

[hadley]

You need to be explicit filter(mydf, is.na(y) | y != "a")