# [R] Puzzled over "partial"

Andrew Simmons @kw@|mmo @end|ng |rom gm@||@com
Mon Jul 26 14:58:35 CEST 2021

```Hello,

First, your statement can be re-written as

sort(x,partial=p)[p]

since n - (n - p) is p. Second, you need to look at

?sort

And look at section "Arguments" subsection "partial", that should have the
details you're looking for. From what I understand, it guarantees that the
indices of "partial" will be sorted correctly, but all others won't, so
this saves time for things like "median". I hope this helps!

On Mon, Jul 26, 2021, 07:54 Nick Wray <nickmwray using gmail.com> wrote:

> Hello   I am puzzled about the use or status of "partial" in R.  years ago
> I found a little piece of code which gives the pth largest number in a
> vector:
> x<-c(5,4,7,2,6,9)
> n <- length(x)
> p<-4
> sort(x,partial=n-(n-p))[n-(n-p)]
> This works fine, although I have tried playing around with the code and
> don't understand what "partial" is doing here.
> However, wanted to work out what was going on, so I looked for "partial in
> r" on t'internet and got this site:Partial apply a function, filling in
> some arguments. — partial • purrr (tidyverse.org)
> <
> https://purrr.tidyverse.org/reference/partial.html#:~:text=Source%3A%20R%2Fpartial.R%20Partial%20function%20application%20allows%20you%20to,that%20an%20argument%20can%20only%20be%20partialised%20once
> .>
> Examples:
> # Partial is designed to replace the use of anonymous functions for #
> <https://purrr.tidyverse.org/reference/keep.html>(x, is.null) # we can
> write: compact2 <- partial(discard, .p = is.null) # partial() works fine
> with functions that do non-standard # evaluation my_long_variable <- 1:10
> plot2 <- partial(plot, my_long_variable) plot2()
> when i tried to run the examples on this site I got error messages - R
> (studio) did not recognise the "partial" function here.  The site did not
> say that I needed a particular package to run the "partial" function.
> Are there essentially two different things in R both described as "partial"
> but which are actually different entities?
> Thanks for any elucidation
> Nick Wray
>
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>
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