Removing NA observations with dplyr::filter()

Question

My data looks like this:

library(tidyverse)  df <- tribble(     ~a, ~b, ~c,     1, 2, 3,      1, NA, 3,      NA, 2, 3 ) 

I can remove all NA observations with drop_na():

df %>% drop_na() 

Or remove all NA observations in a single column (a for example):

df %>% drop_na(a) 

Why can't I just use a regular != filter pipe?

df %>% filter(a != NA) 

Why do we have to use a special function from tidyr to remove NAs?

Answer 1

For example:

you can use:

df %>% filter(!is.na(a)) 

to remove the NA in column a.