alamb commented on a change in pull request #8211:
URL: https://github.com/apache/arrow/pull/8211#discussion_r497443225
##########
File path: rust/arrow/src/array/array.rs
##########
@@ -693,6 +694,61 @@ impl fmt::Debug for PrimitiveArray<BooleanType> {
}
}
+impl<'a, T: ArrowPrimitiveType> IntoIterator for &'a PrimitiveArray<T> {
+ type Item = Option<<T as ArrowPrimitiveType>::Native>;
+ type IntoIter = PrimitiveIter<'a, T>;
+
+ fn into_iter(self) -> Self::IntoIter {
+ PrimitiveIter::<'a, T>::new(self)
+ }
+}
+
+impl<'a, T: ArrowPrimitiveType> PrimitiveArray<T> {
+ /// constructs a new iterator
+ pub fn iter(&'a self) -> PrimitiveIter<'a, T> {
+ PrimitiveIter::<'a, T>::new(&self)
+ }
+}
+
+impl<T: ArrowPrimitiveType, Ptr: Borrow<Option<<T as
ArrowPrimitiveType>::Native>>>
+ FromIterator<Ptr> for PrimitiveArray<T>
+{
+ fn from_iter<I: IntoIterator<Item = Ptr>>(iter: I) -> Self {
+ let iter = iter.into_iter();
+ let (_, data_len) = iter.size_hint();
+ let data_len = data_len.unwrap(); // panic if no upper bound.
Review comment:
```suggestion
let data_len = data_len.expect("Iterator must be sized"); // panic
if no upper bound.
```
##########
File path: rust/arrow/src/compute/kernels/cast.rs
##########
@@ -590,37 +590,27 @@ where
FROM::Native: num::NumCast,
TO::Native: num::NumCast,
{
- numeric_cast::<FROM, TO>(
+ Ok(Arc::new(numeric_cast::<FROM, TO>(
from.as_any()
.downcast_ref::<PrimitiveArray<FROM>>()
.unwrap(),
- )
- .map(|to| Arc::new(to) as ArrayRef)
+ )))
}
/// Natural cast between numeric types
-fn numeric_cast<T, R>(from: &PrimitiveArray<T>) -> Result<PrimitiveArray<R>>
+fn numeric_cast<T, R>(from: &PrimitiveArray<T>) -> PrimitiveArray<R>
where
T: ArrowNumericType,
R: ArrowNumericType,
T::Native: num::NumCast,
R::Native: num::NumCast,
{
- let mut b = PrimitiveBuilder::<R>::new(from.len());
-
- for i in 0..from.len() {
- if from.is_null(i) {
- b.append_null()?;
- } else {
- // some casts return None, such as a negative value to
u{8|16|32|64}
- match num::cast::cast(from.value(i)) {
- Some(v) => b.append_value(v)?,
- None => b.append_null()?,
- };
- }
- }
-
- Ok(b.finish())
+ from.iter()
Review comment:
this is a nice change.
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