[arrow-cast] Support cast numeric to string view #6719
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Signed-off-by: Tai Le Manh <manhtai.lmt@gmail.com>
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@Omega359 During the code review, I found that it is possible to implement support cast for all numeric values ( |
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arrow-cast/src/cast/string.rs
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| let nulls = array.nulls(); | ||
| for i in 0..array.len() { | ||
| match nulls.map(|x| x.is_null(i)).unwrap_or_default() { | ||
| false => builder.append_value(formatter.value(i).try_to_string()?), |
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It would be more optimal to use the std::fmt::write support as for StringArray above.
As written this will allocate for every value which will be very expensive
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@tustvold Thanks so much for reviewing.
It would be more optimal to use the std::fmt::write support as for StringArray above.
As written this will allocate for every value which will be very expensive
I get it now. Will try to implement it. TYSM ❤️
Signed-off-by: Tai Le Manh <manhtai.lmt@gmail.com>
arrow-cast/src/cast/mod.rs
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| @@ -1462,6 +1464,9 @@ pub fn cast_with_options( | |||
| (BinaryView, _) => Err(ArrowError::CastError(format!( | |||
| "Casting from {from_type:?} to {to_type:?} not supported", | |||
| ))), | |||
| (from_type, Utf8View) if from_type.is_primitive() => { | |||
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I believe this also fixes the Timestamp -> Utf8View issue. It would be good to have tests for temporal -> Utf8View added to cover this case.
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After reviewing the code, I realized that the Timestamp -> Utf8View cast is not supported yet.
The main issue comes from the current implementation of formatter.format.write (source) which currently only applies to DisplayIndex derives (source), but the Temporal datatype is implemented based on DisplayIndexState (source).
I think this issue deserves a separate PR to handle the temporal -> string view casting.
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I'll file another PR today to cover the temporal -> Utf8View case unless someone beats me to it.
Signed-off-by: Tai Le Manh <manhtai.lmt@gmail.com>
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Which issue does this PR close?
Closes #6714.
Rationale for this change
Add support cast from numeric(
Int/Float/Decimal) to string view (Utf8View).What changes are included in this PR?
The cast logic and corresponding unit tests.
Are there any user-facing changes?
No.