NA Action of Filter of Dplyr

Thu, Jun 8, 2017

filter in dplyr will drop NAs when we filter a variable bigger or less than certain value.

require(dplyr)

## Loading required package: dplyr

## 
## Attaching package: 'dplyr'

## The following objects are masked from 'package:stats':
## 
##     filter, lag

## The following objects are masked from 'package:base':
## 
##     intersect, setdiff, setequal, union

test <- data.frame(value = c(rep(NA,3), -3:3))

The result of `filter` function

dplyr::filter(test, value > 0)

##   value
## 1     1
## 2     2
## 3     3

test$value[test$value > 0]

## [1] NA NA NA  1  2  3

If we use filter, the result would drop NA observations.

if we use base functions, the NAs are remained.