nevi-me commented on a change in pull request #10063:
URL: https://github.com/apache/arrow/pull/10063#discussion_r614422348
##########
File path: rust/arrow/src/record_batch.rs
##########
@@ -103,6 +103,56 @@ impl RecordBatch {
RecordBatch { schema, columns }
}
+ /// Creates a new [`RecordBatch`] with no columns
+ ///
+ /// TODO add an code example using `append`
+ pub fn new() -> Self {
+ Self {
+ schema: Arc::new(Schema::empty()),
+ columns: Vec::new(),
+ }
+ }
+
+ /// Appends the `field_array` array to this `RecordBatch` as a
+ /// field named `field_name`.
+ ///
+ /// TODO: code example
+ ///
+ /// TODO: on error, can we return `Self` in some meaningful way?
+ pub fn append(self, field_name: &str, field_values: ArrayRef) ->
Result<Self> {
Review comment:
Given that `ArrayRef` is backed by an `Arc`, how about taking it by
reference then cloning it?
Am I correct that if this errors, the underlying `ArrayRef` could get
dropped if it's not a clone in itself?
Something like:
```rust
let array = Int32Array::from(vec![1, 2, 3]);
let array_ref = Arc::new(array);
// append to existing batch
let mut batch = ...;
// assume that this fails, does array_ref get dropped as we no longer have
references to it?
batch = batch.append("ints", array_ref)?;
```
##########
File path: rust/arrow/src/record_batch.rs
##########
@@ -103,6 +103,56 @@ impl RecordBatch {
RecordBatch { schema, columns }
}
+ /// Creates a new [`RecordBatch`] with no columns
+ ///
+ /// TODO add an code example using `append`
+ pub fn new() -> Self {
Review comment:
I think it's worthwhile to maintain the property that a recordbatch is
ummutable. So, this feels a bit out of place for me.
How about we create a builder that takes an iterator of `(&str, ArrayRef)`
instead?
The below is what I mean by out of place
```rust
let mut batch = read_batch_from_somewhere()?;
batch = batch.append("field", array_ref)?;
```
There might be a benefit in having the above, so I'm open to convincing :)
This could partially address your question on the TODO about returning
`Self` on error
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