How to use logical operator (!) with magrittr in R

问题

I am taking a list of values and trying to find those that are not NA using magrittr. Here is a simple example:

data.frame(data = c(1:2, NA, 4:5, NA, 7)) %>% is.na

which yields the correct result:

      data
[1,] FALSE
[2,] FALSE
[3,]  TRUE
[4,] FALSE
[5,] FALSE
[6,]  TRUE
[7,] FALSE

When I put the not operator ! in front of is.na, I get an error:

data.frame(data = c(1:2, NA, 4:5, NA, 7)) %>% !is.na

gives me

Error in FUN(left, right) : operations are possible only for numeric, logical or complex types

After many trials, I stumbled upon this, which works:

 data.frame(data = c(1:2, NA, 4:5, NA, 7)) %>% is.na %>% !.

      data
[1,]  TRUE
[2,]  TRUE
[3,] FALSE
[4,]  TRUE
[5,]  TRUE
[6,] FALSE
[7,]  TRUE

My question is whether there is a different way to do this. There are other alias options in the package but I don't see any examples of them. One is "not". Maybe I should be using that instead?

I realize that I have answered my question to some degree, but I would like to know if this can be done without having to resort to %>% !. at the end.

回答1:

Why not just move the negation to the "front". This is how you typically negate the %in% infix operatiuon

 !data.frame(data = c(1:2, NA, 4:5, NA, 7)) %>% is.na

      data
[1,]  TRUE
[2,]  TRUE
[3,] FALSE
[4,]  TRUE
[5,]  TRUE
[6,] FALSE
[7,]  TRUE

回答2:

You can use backticks to pipe your result into the function underlying the operator:

> data.frame(data = c(1:2, NA, 4:5, NA, 7)) %>% is.na %>% `!`
      data
[1,]  TRUE
[2,]  TRUE
[3,] FALSE
[4,]  TRUE
[5,]  TRUE
[6,] FALSE
[7,]  TRUE

Alternatively use the Negate function:

> data.frame(data = c(1:2, NA, 4:5, NA, 7)) %>% Negate(is.na)()
      data
[1,]  TRUE
[2,]  TRUE
[3,] FALSE
[4,]  TRUE
[5,]  TRUE
[6,] FALSE
[7,]  TRUE

回答3:

Or even

data.frame(data = c(1:2, NA, 4:5, NA, 7)) %>% 
  is.na %>% 
 `n'est pas`

来源：https://stackoverflow.com/questions/25345244/how-to-use-logical-operator-with-magrittr-in-r

标签

magrittr