that `[.data.frame` and
>`[<-.data.frame` are _not_ primitive functions, positional matching is done
>there as well. Sometimes. At least when 'x' argument is not first, as shown in
>Bill's examples. Obviously my "test" was insufficient...
>
>Cheers,
>
>Henrik
From: William Dunlap
Sent: Wednesday, November 28, 2018 9:10 PM
To: Henrik Pärn
Cc: r-devel@r-project.org
Subject: Re: [Rd] named arguments discouraged in `[.data.frame` and
`[<-.data.frame`
They can get bitten in the last two lines of this exa
there as well. Sometimes. At least when 'x' argument is not first, as shown in
Bill's examples. Obviously my "test" was insufficient...
Cheers,
Henrik
From: William Dunlap
Sent: Wednesday, November 28, 2018 9:10 PM
To: Henrik Pärn
Cc: r-devel@r-project.org
Subject: Re: [Rd] na
They can get bitten in the last two lines of this example, where the 'x'
argument is not first:
> d <- data.frame(C1=c(r1=11,r2=21,r3=31), C2=c(12,22,32))
> d[1,1:2]
C1 C2
r1 11 12
> `[`(d,j=1:2,i=1)
C1 C2
r1 11 12
Warning message:
In `[.data.frame`(d, j = 1:2, i = 1) :
named arguments
Whenever they are calling a primitive, because primitives match
arguments positionally. Of course, you then you need to introduce the
concept of a primitive.
You could also make an argument from the code clarity perspective, as
typically primitives have simple interfaces and/or are used
tl;dr:
Why are named arguments discouraged in `[.data.frame`, `[<-.data.frame` and
`[[.data.frame`?
(because this question is of the kind 'why is R designed like this?', I though
R-devel would be more appropriate than R-help)
#
Background:
Now and then students
