[Python] Does Array.unique preserve order?

[MarcoGorelli]

Describe the usage question you have. Please include as many useful details as possible.

It looks like Array.unique maintains the order of elements' appearance:

In [30]: pa.array([1, 1, 2, 2, 1, 4, 2]).unique()
Out[30]:
<pyarrow.lib.Int64Array object at 0x7f48661a9900>
[
  1,
  2,
  4
]

Is this guaranteed to always be the case? If so, would you be open to documenting the guarantee?

Component(s)

Python