Using the pipe, |>, syntax with "names<-"
That was supposed to be z |> list(x = _) |> within(names(x) <- replace(names(x), 2, "foo")) |> _$x but I really see no advantage over z |> list(x = _) |> within(names(x)[2] <- "foo") |> _$x Regarding the z |> names() |> _[2] <- "foo" idiom, while it is clever, and well illustrates what is possible with base R pipes that might not be initially expected, I think it should be discouraged as not in the spirit of pipes which is a more functional approach to programming. Such an approach ought to be non-destructive and should pass on the result to the next step in the pipeline. These criteria are not satisfied by it. On Sun, Jul 21, 2024 at 11:17?AM Gabor Grothendieck
<ggrothendieck at gmail.com> wrote:
If you object to names(x)[2]<- ... then use replace: z |> list(x = _) |> within(replace(names(x), 2, "foo")) |> _$x On Sun, Jul 21, 2024 at 11:10?AM Bert Gunter <bgunter.4567 at gmail.com> wrote:
hmmm... But note that you still used the nested assignment, names()[2] <- "foo", to circumvent R's pipe limitations, which is exactly what Iris's solution avoids. So I think I was overawed by your cleverness ;-) Best, Bert On Sun, Jul 21, 2024 at 8:01?AM Bert Gunter <bgunter.4567 at gmail.com> wrote:
Wow! Yes, this is very clever -- way too clever for me -- and meets my criteria for a solution. I think it's also another piece of evidence of why piping in base R is not suited for complex/nested assignments, as discussed in Deepayan's response. Maybe someone could offer a better Tidydata piping solution just for completeness? Best, Bert On Sun, Jul 21, 2024 at 7:48?AM Gabor Grothendieck <ggrothendieck at gmail.com> wrote:
This - is non-destructive (does not change z) - passes the renamed z onto further pipe legs - does not use \(x)... It works by boxing z, operating on the boxed version and then unboxing it. z <- data.frame(a = 1:3, b = letters[1:3]) z |> list(x = _) |> within(names(x)[2] <- "foo") |> _$x ## a foo ## 1 1 a ## 2 2 b ## 3 3 c On Sat, Jul 20, 2024 at 4:07?PM Bert Gunter <bgunter.4567 at 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
______________________________________________ R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
-- Statistics & Software Consulting GKX Group, GKX Associates Inc. tel: 1-877-GKX-GROUP email: ggrothendieck at gmail.com
-- Statistics & Software Consulting GKX Group, GKX Associates Inc. tel: 1-877-GKX-GROUP email: ggrothendieck at gmail.com
Statistics & Software Consulting GKX Group, GKX Associates Inc. tel: 1-877-GKX-GROUP email: ggrothendieck at gmail.com