[ARROW-9083] [R] collect int64, uint32, uint64 as R integer type if not out of bounds

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 1.0.0
• Component/s: R
• Labels: pull-request-available
• External issue URL: https://github.com/apache/arrow/issues/25198
• Assignee: Neal Richardson
• Reporter: Neal Richardson
• Created: 09/Jun/20 17:45
• Updated: 11/Jan/23 08:04
• Resolved: 01/Jul/20 15:48

Description

bit64::integer64 can be awkward to work with in R (one example: https://github.com/apache/arrow/issues/7385). Often in Arrow we get int64 types from compute methods or other translation methods that auto-promote to the largest integer type, but they would fit fine in a 32-bit integer, which is R's native type.

When calling Array__as_vector on an int64, we could first call the minmax function on the array, and if the extrema are within the range of a 32-bit int, return a regular R integer vector. This would add a little bit of ambiguity as to what R type you'll get from an Arrow type, but I wonder if the benefits are worth it since you can't do much with an integer64 in R. (We could also make this optional, similar to ARROW-7657, so you could specify a "strict" mode if you are in a use case where roundtrip fidelity is more important than R usability.)

Likewise, uint32 and uint64 could be kept as integers and prevent the conversion to double that is currently implemented.

Issue Links

• is related to: ARROW-9118 [C++] Add more general BoundsCheck function that also checks for arbitrary lower limits in integer arrays
• relates to: ARROW-3446 [R] Document mapping of Arrow <-> R types
• links to: GitHub Pull Request #7602