我的数据如下所示:
library(tidyverse)
df <- tribble(
~a, ~b, ~c,
1, 2, 3,
1, NA, 3,
NA, 2, 3
)
我可以用drop_na()删除所有NA个观察值:
df %>% drop_na()
或者删除单个列中的所有NA个观察值(例如a个):
df %>% drop_na(a)
为什么我不能用普通的!=过滤管呢？
df %>% filter(a != NA)
为什么我们必须使用tidyr的特殊功能来删除NAs？
来自@Ben Bolker:
[T] his与dplyr::filter()没有具体关系
来自@Marat Talipov:
[A] ny与NA的比较，包括NA==NA，将返回NA
来自@farnsy的related answer篇文章:
==运算符并不像您期望的那样对待NA.
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不知道你在分析什么，所以