eddelbuettel commented on issue #810:
URL:
https://github.com/apache/arrow-nanoarrow/issues/810#issuecomment-3335902755
A slightly refined and cleaned up version, which needs a small extension to
the archived `xptr` CRAN package (which I'll likely resurrect and re-send to
CRAN, author/former maintainer is on board) to create '%lld' output which we
can `r_to_py()` so that `int()` can take them:
```r
capsule_prep <- function(na) {
## pointer addresses for array and schema in 'long long int' format
arrchr <- xptr::xptr_address(na, FALSE)
schchr <- xptr::xptr_address(xptr::xptr_tag(na), FALSE)
## Import with convert = FALSE so that `_import_from_c` returns a Python
object
py <- reticulate::import_builtins(convert = FALSE)
pa <- reticulate::import("pyarrow", convert = FALSE)
out <- pa$Array$`_import_from_c`(py$int(reticulate::r_to_py(arrchr)),
py$int(reticulate::r_to_py(schchr)))
out
}
```
If I wrap that around my `nanoarrow`-created `RecordBatch` then I can send
this to Python as in
```r
pa <- import("pyarrow")
na2 <- capsule_prep(narb) # narb is the nanoarrow-create record batch
object
## create a record batch
df <- pa$record_batch(na2)
## which we can turn into a table
## which can be exported to pandas
print(pa$table(df)$to_pandas())
```
The question (mostly to @paleolimbot) now is: can something like this
(possibly without the `xptr` dependence, this is easy to replicate here /
already exists) be injected here in an elegant way / possibly with S3 magic to
be 'automagically' invoked? I am a little unclear on how a `nanoarrow` object
would know it is become a Python object ...
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