tustvold commented on code in PR #5798:
URL: https://github.com/apache/arrow-rs/pull/5798#discussion_r1613560755
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arrow-array/src/array/primitive_array.rs:
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@@ -480,6 +480,19 @@ pub use crate::types::ArrowPrimitiveType;
/// assert_eq!(array.values(), &[1, 0, 2]);
/// assert!(array.is_null(1));
/// ```
+///
+/// # Example: Get a `PrimitiveArray` from an [`ArrayRef`]
+/// ```
+/// # use std::sync::Arc;
+/// # use arrow_array::{Array, ArrayRef, Float32Array, PrimitiveArray};
+/// # use arrow_array::types::{Float32Type};
+/// # use arrow_schema::DataType;
+/// # let array: ArrayRef = Arc::new(Float32Array::from(vec![1.2, 2.3]));
+/// // will panic if the array is not a Float32Array
+/// assert_eq!(&DataType::Float32, array.data_type());
+/// let f32_array = PrimitiveArray::<Float32Type>::from(array.into_data());
Review Comment:
It's likely marginal, but it avoids a fair amount of data marshalling so
should be faster to not go via ArrayData
Edit: You could also use
https://docs.rs/arrow-array/latest/arrow_array/cast/fn.downcast_array.html but
that is just a wrapper around using into_data
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