invalid use of native pipe using underscore _

Question

Example:

mydf <- data.frame(x = 1:10, y = rnorm(10))
mydf[2,2] <- NA
mydf[5,1] <- NA

Looks like:

mydf
    x          y
1   1 -1.0198834
2   2         NA
3   3  0.6080986
4   4 -0.4124830
5  NA  0.1723944
6   6 -2.3869210
7   7 -0.9843615
8   8 -1.3187416
9   9  0.1794670
10 10  0.9708277

I want to replace all NAs in the entire df with 0. I read this blog post then tried:

mydf |> replace(is.na(_), '') # Error in replace(mydf, is.na("_"), "") : invalid use of pipe placeholder
mydf |> mutate(across(everything(), .fns = ~replace_na(_, 0))) # Error in mydf |> mutate(across(everything(), .fns = ~replace_na("_", 0))) : invalid use of pipe placeholder

mydf |> mutate(across(everything(), .fns = ~replace_na(data = _, 0))) # same error, tried passing placeholder to a named arg per the blog post "One thing that is different than the . placeholder is the fact that you need to pass the name of the argument that will receive the _ placeholder"

How can I replace all NA with 0 in my df within my dplyr chain in this way?

You cannot nest the placeholder for the native pipe yet. Probably in the near future. Native placeholder can only be used in the outermost function call — Onyambu, Apr 14 '23 at 08:53

Ronak Shah · Accepted Answer · 2023-04-14T09:16:46.303

The placeholder (_) can be used only once in native pipe.

In mydf |> replace(is.na(_), 0) you are already passing mydf as first argument of replace so you cannot use it again in is.na(_).

You may use an anonymous function call.

mydf |> (\(x) replace(x, is.na(x), 0))()

#    x           y
#1   1 -0.02299403
#2   2  0.00000000
#3   3  0.29872957
#4   4 -0.78494209
#5   0  1.00703929
#6   6 -0.86201001
#7   7  1.26448247
#8   8  0.25913254
#9   9  1.69794293
#10 10  1.28005887

PS - I am sure you are aware of mydf[is.na(mydf)] <- 0

Interesting read What are the differences between R's new native pipe `|>` and the magrittr pipe `%>%`?

invalid use of native pipe using underscore _

1 Answers1