R devel - Sep 2023 - List's `[[` method with "" tag

Hi,

I notice that one can assign a variable to an R list by using an empty
string key but one cannot get that variable back from the list by using the
empty string key:

```r
l <- list()
l[[""]] <- "An empty string as list key"
names(l)
l[[""]] # Returns a `NULL`
l[[names(l) == ""]] # Returns first value with `""` tag
```

Instead of `l[[""]]` returning a `NULL` I'd "expect" it
to instead return
the first variable named `""`  i.e. in this case "An empty string
as list
key".  It would be nice if the `[[` method of a list was updated to
"fix"
this.

Additionally, I observe that if a list is named but has certain elements
without names then those are currently "named" `""`:

```r
names(list(a = 1, 2, c = 3, 4))
```

This latter change may be a breaking change but I speculate that perhaps it
may be more intuitive if missing names were indicated with `NA_character_`
instead of `""`.

Thanks,

Trevor

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It's per design: 

?names
...
The name '""' is special: it is used to
indicate that there is no
name associated with an element of a (atomic
or generic) vector.
Subscripting by '""' will match nothing (not even
elements which
have no name).
... 

Best,
Serguei. 

Le 2023-09-11
18:29, Trevor Davis a ?crit :
> Hi,
> 
> I notice that one can assign a
variable to an R list by using an empty
> string key but one cannot get
that variable back from the list by using the
> empty string key:
> 
>
```r
> l <- list()
> l[[""]] <- "An empty string as list key"
>
names(l)
> l[[""]] # Returns a `NULL`
> l[[names(l) == ""]] # Returns
first value with `""` tag
> ```
> 
> Instead of `l[[""]]` returning a
`NULL` I'd "expect" it to instead return
> the first variable named `""`
i.e. in this case "An empty string as list
> key".  It would be nice if
the `[[` method of a list was updated to "fix"
> this.
> 
>
Additionally, I observe that if a list is named but has certain
elements
> without names then those are currently "named" `""`:
> 
>
```r
> names(list(a = 1, 2, c = 3, 4))
> ```
> 
> This latter change may
be a breaking change but I speculate that perhaps it
> may be more
intuitive if missing names were indicated with
`NA_character_`
> instead
of `""`.
> 
> Thanks,
> 
> Trevor
> 
> [[alternative HTML version
deleted]]
> 
> ______________________________________________
>
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>
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