[Document] Adding UDF by impl ScalarUDFImpl #9172
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create_udf will use SimpleScalarUDF::new, which is not deprecated. The deprecated one is ScalarUDF::new, sorry for my previous wrong understanding.
https://github.com/apache/arrow-datafusion/blob/c9e4b7b7c5c2c2e7b3ea01040a6edeafd151410c/datafusion/expr/src/expr_fn.rs#L982-L996
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| To register a Scalar UDF, you need to wrap the function implementation in a [`ScalarUDF`] struct and then register it with the `SessionContext`. | ||
| DataFusion provides the [`create_udf`] and helper functions to make this easier. | ||
| There is a lower level API with more functionality but is more complex, that is documented in [`advanced_udf.rs`]. |
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I doubt a little that whether my PR is necessary, it seems that there's already a updated link that helps user create scalarUDF by impl trait. 🤔 What do you think ? @alamb
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I think the value of this library guide is the surrounding text, so it seems ok to me to have the code replicated in two places
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| To register a Scalar UDF, you need to wrap the function implementation in a [`ScalarUDF`] struct and then register it with the `SessionContext`. | ||
| DataFusion provides the [`create_udf`] and helper functions to make this easier. | ||
| There is a lower level API with more functionality but is more complex, that is documented in [`advanced_udf.rs`]. |
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I think the value of this library guide is the surrounding text, so it seems ok to me to have the code replicated in two places
| Ok(Arc::new(new_array)) | ||
| } | ||
| } | ||
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I suggest ending the first code block here and then adding a sentence:
We now need to register the function with DataFusion so that it can be used in the context of a query.
(then rest of the example)
Co-authored-by: Andrew Lamb <[email protected]>
Co-authored-by: Andrew Lamb <[email protected]>
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Thanks for your review! @alamb and have applied the suggestions. |
Which issue does this PR close?
Closes #9136.
Rationale for this change
See #9136
What changes are included in this PR?
Document update including adding a scalar udf by
impl ScalarUDFImpl