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Opposite of %in%: exclude rows with values specified in a vector


Question

A categorical variable V1 in a data frame D1 can have values represented by the letters from A to Z. I want to create a subset D2, which excludes some values, say, B, N and T. Basically, I want a command which is the opposite of %in%

D2 = subset(D1, V1 %in% c('B','N',T'))
2020/07/10
1
269
7/10/2020 11:06:54 AM

Accepted Answer

You can use the ! operator to basically make any TRUE FALSE and every FALSE TRUE. so:

D2 = subset(D1, !(V1 %in% c('B','N','T')))

EDIT: You can also make an operator yourself:

'%!in%' <- function(x,y)!('%in%'(x,y))

c(1,3,11)%!in%1:10
[1] FALSE FALSE  TRUE
2018/09/27
364
9/27/2018 10:04:16 PM

How about:

'%ni%' <- Negate('%in%')
c(1,3,11) %ni% 1:10
# [1] FALSE FALSE  TRUE
2018/03/01

If you look at the code of %in%

 function (x, table) match(x, table, nomatch = 0L) > 0L

then you should be able to write your version of opposite. I use

`%not in%` <- function (x, table) is.na(match(x, table, nomatch=NA_integer_))

Another way is:

function (x, table) match(x, table, nomatch = 0L) == 0L
2011/04/29

Here is a version using filter in dplyr that applies the same technique as the accepted answer by negating the logical with !:

D2 <- D1 %>% dplyr::filter(!V1 %in% c('B','N','T'))
2018/06/28

Using negate from purrr also does the trick quickly and neatly:

`%not_in%` <- purrr::negate(`%in%`)

Then usage is, for example,

c("cat", "dog") %not_in% c("dog", "mouse")
2018/05/22

purrr::compose() is another quick way to define this for later use, as in:

`%!in%` <- compose(`!`, `%in%`)
2018/05/09

Source: https://stackoverflow.com/questions/5831794
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