Ah - the Result is for error handling. So either:
1) Return arrow::Status from this function, and use the ARROW_ASSIGN_OR_RAISE
macro:
ARROW_ASSIGN_OR_RAISE(auto scalar, arrow::MakeScalar(...));
..., cp::literal(std::move(scalar)) ...
2) For experimentation purposes, just assume it'll succeed:
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
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 wrote:
> H
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
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 wrote:
>
> Gotcha. Thanks for the pointer!
>
> On Thu, Feb 3, 2022 at 11:0
Gotcha. Thanks for the pointer!
On Thu, Feb 3, 2022 at 11:06 AM Rok Mihevc 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:
> aut
> 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
Gotcha. "Assume timezone" is like "tz_localize" in pandas.
> If you are starting from a UTC-zoned timestamp you can just cast it,
as David suggests, to the desired timezone (this is a metadata only
change)
I didn't see any target timezone information being passed in the "cast"
function - how woul
Assume_timezone will "assume timezone" of the local time you pass it
and give you a zoned timestamp. This means your timestamps will be
interpreted as local times and converted to UTC in the background.
Resulting array will have timezone metadata of your assumed timezone.
If you are starting from
David - Thanks for the pointers. I didn't know you could cast a timestamp
to time type to extract the hour/minute information. Nice!
Rok - Not sure I understand what you mean... My input is UTC but I want to
extract the time information local to New York Timezone (e.g. filter time
to 10 AM New Yo
Hey Li,
If your input data is in UTC you don't need assume_timezone [1]. You
would need it if your input was America/New_York local time and you
wanted to convert to a zoned timestamp array where underlying data is
in UTC and timezone is metadata only. Perhaps python tests are
interesting for refe
We just added some documentation and examples around the C++ ExecPlan:
- https://arrow.apache.org/docs/dev/cpp/streaming_execution.html
-
https://github.com/apache/arrow/blob/master/cpp/examples/arrow/execution_plan_documentation_examples.cc
For this, "cast" should work. Here's an example in Pyt
Hello!
I am new to the Arrow C++ compute engine and trying to figure out this time
zone conversion and time extraction:
t.dt.tz_convert('America/New_York').dt.time == datetime.time(11, 30, 0)
So I started looking at:
https://github.com/apache/arrow/blob/master/cpp/src/arrow/compute/kernels/scala
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