[ARROW-15477] [C++][Python] Enable ListArray::FromArrays with custom list type (field names/nullability)

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 8.0.0
• Component/s: C++, Python
• Labels: pull-request-available
• External issue URL: https://github.com/apache/arrow/issues/30953
• Assignee: Joris Van den Bossche
• Reporter: Joris Van den Bossche
• Created: 27/Jan/22 14:51
• Updated: 11/Jan/23 11:37
• Resolved: 02/Feb/22 13:26

Description

Currently, when creating a ListArray from the values and offets, you get a "default" list type:

>>> arr = pa.ListArray.from_arrays(pa.array([0, 2, 5], pa.int32()), pa.array([1, 2, 3, 4, 5]))
>>> arr
<pyarrow.lib.ListArray object at 0x7f75bdf03dc0>
[
  [
    1,
    2
  ],
  [
    3,
    4,
    5
  ]
]

>>> arr.type
ListType(list<item: int64>)

So a type with default field name ("item") and nullability (true).
We should allow to specify a type (that needs to be compatible with the passed values' type) so you can create a ListArray with specific field names.

Issue Links

• links to: GitHub Pull Request #12312