Re: [Rd] Should subsetting named vector return named vector including named unmatched elements?
Never been a big fan of this behavior either but maybe the intention was
to make it easier to distinguish between 2 types of NAs in the result:
those that were present in the original vector vs those that are
introduced by an unmatched subscript. Like in this example:
x <- setNames(c(101:108, NA), letters[1:9])
x
# a b c d e f g h i
# 101 102 103 104 105 106 107 108 NA
x[c("g", "k", "a", "i")]
# g a i
# 107 NA 101 NA
The first NA is the result of an unmatched subscript, while the second
one comes from 'x'.
This is of limited interest though. In most real world applications I've
worked on, we actually need to "fix" the names of the result.
Best,
H.
On 1/18/24 11:51, Jiří Moravec wrote:
> Subsetting vector (including lists) returns the same number of
> elements as the subsetting vector, including unmatched elements which
> are reported as `NA` or `NULL` (in case of lists).
>
> Consider:
>
> ```
> menu = list(
> "bacon" = "foo",
> "eggs" = "bar",
> "beans" = "baz"
> )
>
> select = c("bacon", "eggs", "spam")
>
> menu[select]
> # $bacon
> # [1] "foo"
> #
> # $eggs
> # [1] "bar"
> #
> # $
> # NULL
>
> ```
>
> Wouldn't it be more logical to return named vector/list including
> names of unmatched elements when subsetting using names? After all,
> the unmatched elements are already returned. I.e., the output would
> look like this:
>
> ```
>
> menu[select]
> # $bacon
> # [1] "foo"
> #
> # $eggs
> # [1] "bar"
> #
> # $spam
> # NULL
>
> ```
>
> The simple fix `menu[select] |> setNames(select)` solves, but it feels
> to me like something that could be a default behaviour.
>
> On slightly unrelated note, when I was asking if there is a better
> solution, the `menu[select]` seems to allocate more memory than
> `menu_env = list2env(menu); mget(select, envir = menu, ifnotfound =
> list(NULL)`. Or the sapply solution. Is this a benchmarking artifact?
>
> https://stackoverflow.com/q/77828678/4868692
>
> __
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--
Hervé Pagès
Bioconductor Core Team
hpages.on.git...@gmail.com
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Re: [Rd] Should subsetting named vector return named vector including named unmatched elements?
Jiří,
For your first question, the NA names make sense if you think of indexing with
a character vector as the same as menu[match(select, names(menu))]. You're not
indexing with "beans"; rather, "beans" becomes NA because it's not in the names
of menu. (This is how it's documented in ?`[`: "Character vectors will be
matched to the names of the object...")
Steve
On Thursday, January 18th, 2024 at 2:51 PM, Jiří Moravec
wrote:
> Subsetting vector (including lists) returns the same number of elements
> as the subsetting vector, including unmatched elements which are
> reported as `NA` or `NULL` (in case of lists).
>
> Consider:
>
> ```
> menu = list(
> "bacon" = "foo",
> "eggs" = "bar",
> "beans" = "baz"
> )
>
> select = c("bacon", "eggs", "spam")
>
> menu[select]
> # $bacon
> # [1] "foo"
> #
> # $eggs
> # [1] "bar"
> #
> # $
>
> # NULL
>
> `Wouldn't it be more logical to return named vector/list including names of
> unmatched elements when subsetting using names? After all, the unmatched
> elements are already returned. I.e., the output would look like this:`
>
> menu[select]
> # $bacon
> # [1] "foo"
> #
> # $eggs
> # [1] "bar"
> #
> # $spam
> # NULL
>
> ```
>
> The simple fix `menu[select] |> setNames(select)` solves, but it feels
>
> to me like something that could be a default behaviour.
>
> On slightly unrelated note, when I was asking if there is a better
> solution, the `menu[select]` seems to allocate more memory than
> `menu_env = list2env(menu); mget(select, envir = menu, ifnotfound =
> list(NULL)`. Or the sapply solution. Is this a benchmarking artifact?
>
> https://stackoverflow.com/q/77828678/4868692
>
> __
> R-devel@r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-devel
__
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[Rd] Should subsetting named vector return named vector including named unmatched elements?
Subsetting vector (including lists) returns the same number of elements
as the subsetting vector, including unmatched elements which are
reported as `NA` or `NULL` (in case of lists).
Consider:
```
menu = list(
"bacon" = "foo",
"eggs" = "bar",
"beans" = "baz"
)
select = c("bacon", "eggs", "spam")
menu[select]
# $bacon
# [1] "foo"
#
# $eggs
# [1] "bar"
#
# $
# NULL
```
Wouldn't it be more logical to return named vector/list including names
of unmatched elements when subsetting using names? After all, the
unmatched elements are already returned. I.e., the output would look
like this:
```
menu[select]
# $bacon
# [1] "foo"
#
# $eggs
# [1] "bar"
#
# $spam
# NULL
```
The simple fix `menu[select] |> setNames(select)` solves, but it feels
to me like something that could be a default behaviour.
On slightly unrelated note, when I was asking if there is a better
solution, the `menu[select]` seems to allocate more memory than
`menu_env = list2env(menu); mget(select, envir = menu, ifnotfound =
list(NULL)`. Or the sapply solution. Is this a benchmarking artifact?
https://stackoverflow.com/q/77828678/4868692
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