Removing NA observations with dplyr::filter()

RDplyr

R Problem Overview

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?

R Solutions

Solution 1 - R

For example:

you can use:

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

to remove the NA in column a.

Solution 2 - R

If someone is here in 2020, after making all the pipes, if u pipe %>% na.exclude will take away all the NAs in the pipe!

Solution 3 - R

From @Ben Bolker:

> [T]his has nothing specifically to do with dplyr::filter()

From @Marat Talipov:

> [A]ny comparison with NA, including NA==NA, will return NA

From a related answer by @farnsy:

> The == operator does not treat NA's as you would expect it to. > > Think of NA as meaning "I don't know what's there". The correct answer > to 3 > NA is obviously NA because we don't know if the missing value > is larger than 3 or not. Well, it's the same for NA == NA. They are > both missing values but the true values could be quite different, so > the correct answer is "I don't know." > > R doesn't know what you are doing in your analysis, so instead of > potentially introducing bugs that would later end up being published > an embarrassing you, it doesn't allow comparison operators to think NA > is a value.

Solution 4 - R

I always use this and it is working perfectly

cool$day[cool$day==''] <- NA  
cool$day[is.na(cool$day)] <- "NA"

cool <- cool[!cool$day == "NA", ]
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Content TypeOriginal AuthorOriginal Content on Stackoverflow
QuestionemehexView Question on Stackoverflow
Solution 1 - RJeffZhengView Answer on Stackoverflow
Solution 2 - RshackeView Answer on Stackoverflow
Solution 3 - RemehexView Answer on Stackoverflow
Solution 4 - RAnya StiView Answer on Stackoverflow