I suspect that you would want to define a function which was aware of the limitations of piping to handle this. For example:

rename <- function(x, col, newname) {
  names(x)[col] <- newname
  x
}

Then

z |> rename(2, "foo")

would be fine.

Duncan Murdoch

On 2024-07-20 4:46 p.m., Bert Gunter wrote:
With further fooling around, I realized that explicitly assigning my
last "solution" 'works'; i.e.

names(z)[2] <- "foo"

can be piped as:

  z <- z |>(\(x) "names<-"(x,value = "[<-"(names(x),2,'foo')))()
z
   a foo
1 1   a
2 2   b
3 3   c

This is even awfuller than before. So my query still stands.

-- Bert

On Sat, Jul 20, 2024 at 1:14 PM Bert Gunter <bgunter.4...@gmail.com> wrote:

Nope, I still got it wrong: None of my approaches work.  :(

So my query remains: how to do it via piping with |> ?

Bert


On Sat, Jul 20, 2024 at 1:06 PM Bert Gunter <bgunter.4...@gmail.com> wrote:

This post is likely pretty useless;  it is motivated by a recent post
from "Val" that was elegantly answered using Tidyverse constructs, but
I wondered how to do it using base R only. Along the way, I ran into
the following question to which I think my answer (below) is pretty
awful. I would be interested in more elegant base R approaches. So...

z <- data.frame(a = 1:3, b = letters[1:3])
z
   a h
1 1 a
2 2 b
3 3 c

Suppose I want to change the name of the second column of z from 'b'
to 'foo' . This is very easy using nested function syntax by:

names(z)[2] <- "foo"
z
   a foo
1 1   a
2 2   b
3 3   c

Now suppose I wanted to do this using |> syntax, along the lines of:

z |> names()[2] <- "foo"  ## throws an error

Slightly fancier is:

z |> (\(x)names(x)[2] <- "b")()
## does nothing, but does not throw an error.

However, the following, which resulted from a more careful read of
?names works (after changing the name of the second column back to "b"
of course):

z |>(\(x) "names<-"(x,value = "[<-"(names(x),2,'foo')))()
z
   a foo
1 1   a
2 2   b
3 3   c

This qualifies to me as "pretty awful." I'm sure there are better ways
to do this using pipe syntax, so I would appreciate any better
approaches.

Best,
Bert

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