So I think I am getting close... now I have
cp::Expression predicate = cp::call(
"equal",
{...}
cp::literal(arrow::MakeScalar(arrow::time64(arrow::TimeUnit::NANO), time))}
);
And got
/usr/include/arrow/compute/exec/expression.h:143:18: error: no matching
conversion for functional-style cast from
'arrow::Result<std::shared_ptr<arrow::Scalar>>' to 'arrow::Datum'
return literal(Datum(std::forward<Arg>(arg)));
^~~~~~~~~~~~~~~~~~~~~~~~~~~~
/home/icexelloss/workspace/bamboo-streaming/examples/msw_filter_time.cc:66:44:
note: in instantiation of function template
specialization
'arrow::compute::literal<arrow::Result<std::shared_ptr<arrow::Scalar>>>'
requested here
cp::literal(arrow::MakeScalar(arrow::time64(arrow::TimeUnit::NANO), time))}
Any help / pointers are much appreciated!
On Mon, Feb 7, 2022 at 12:13 PM Li Jin <ice.xell...@gmail.com> wrote:
> Another question - what is the correct way of creating a constant Scalar
> that represents a time64 from a string in C++ (e.g. "10:00:00") ?
>
> I am trying to use cp::literal(arrow::MakeScalar(...)) but not sure what
> to fill in the body of MakeScalar
>
> On Mon, Feb 7, 2022 at 12:05 PM Li Jin <ice.xell...@gmail.com> wrote:
>
>> Hello,
>>
>> Did some more work on this. Follow up question on this:
>>
>> I am doing a
>>
>> {cp::call("cast",
>>
>> {cp::field_ref("time_ns")},
>>
>> cp::CastOptions::Safe(arrow::timestamp(arrow::TimeUnit::NANO, timezone)))},
>>
>> And got:
>>
>> NotImplemented: Unsupported cast from uint64 to timestamp using function
>> cast_timestamp
>>
>> Is this the wrong way to convert uint64 to timestamp or is it just not
>> supported right now?
>>
>> On Thu, Feb 3, 2022 at 12:29 PM Rok Mihevc <rok.mih...@gmail.com> wrote:
>>
>>> By the way - if you're extracting components to segment time you might
>>> prefer temporal rounding
>>>
>>> https://arrow.apache.org/docs/dev/cpp/compute.html?highlight=floor_temporal#conversions
>>> .
>>>
>>> On Thu, Feb 3, 2022 at 5:19 PM Li Jin <ice.xell...@gmail.com> wrote:
>>> >
>>> > Gotcha. Thanks for the pointer!
>>> >
>>> > On Thu, Feb 3, 2022 at 11:06 AM Rok Mihevc <rok.mih...@gmail.com>
>>> wrote:
>>> >
>>> > > > Gotcha. "Assume timezone" is like "tz_localize" in pandas.
>>> > >
>>> > > Indeed!
>>> > >
>>> > > > I didn't see any target timezone information being passed in the
>>> "cast"
>>> > > > function - how would I do that?
>>> > >
>>> > > Just cast with:
>>> > > auto options = CastOptions::Safe(timestamp(TimeUnit::NANO,
>>> > > "America/New_York"));
>>> > > See examples in:
>>> > >
>>> > >
>>> https://github.com/apache/arrow/blob/master/cpp/src/arrow/compute/kernels/scalar_cast_test.cc
>>> > >
>>>
>>
