HaoYang670 commented on code in PR #2297:
URL: https://github.com/apache/arrow-rs/pull/2297#discussion_r938582275
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arrow/src/array/array_dictionary.rs:
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@@ -385,6 +404,86 @@ impl<T: ArrowPrimitiveType> fmt::Debug for
DictionaryArray<T> {
}
}
+/// A strongly-typed wrapper around a [`DictionaryArray`] that implements
[`ArrayAccessor`]
+/// allowing fast access to its elements
+///
+/// ```
+/// use arrow::array::{ArrayIter, DictionaryArray, StringArray};
+/// use arrow::datatypes::Int32Type;
+///
+/// let orig = ["a", "b", "a", "b"];
+/// let dictionary = DictionaryArray::<Int32Type>::from_iter(orig);
+/// let typed = dictionary.downcast_dict::<StringArray>().unwrap();
+///
+/// for (maybe_val, orig) in typed.into_iter().zip(orig) {
+/// assert_eq!(maybe_val.unwrap(), orig)
+/// }
+/// ```
+#[derive(Copy, Clone)]
+pub struct TypedDictionaryArray<'a, K: ArrowPrimitiveType, V> {
+ /// The dictionary array
+ pub dictionary: &'a DictionaryArray<K>,
Review Comment:
Sorry for the late.
I prefer to name it `base`, but never mind, this is really a small tip.
LGTM!
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