Abdullahsab3 commented on code in PR #5826:
URL: https://github.com/apache/arrow-rs/pull/5826#discussion_r1622863186
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arrow-cast/src/cast/mod.rs:
##########
@@ -577,10 +579,95 @@ fn timestamp_to_date32<T: ArrowTimestampType>(
/// (i.e. casting `6.4999` to Decimal(10, 1) becomes `6.5`). Prior to
version `26.0.0`,
/// casting would truncate instead (i.e. outputs `6.4` instead)
///
-/// Unsupported Casts
+/// Unsupported Casts (check with `can_cast_types` before calling):
/// * To or from `StructArray`
/// * List to primitive
/// * Interval and duration
+///
+/// # Timestamps and Timezones
+///
+/// Timestamps are stored with an optional timezone in Arrow.
+///
+/// ## Casting timestamps to a timestamp without timezone / UTC
+/// ```
+/// # use arrow_array::Int64Array;
+/// # use arrow_array::types::TimestampSecondType;
+/// # use arrow_cast::{cast, display};
+/// # use arrow_array::cast::AsArray;
+/// # use arrow_schema::{DataType, TimeUnit};
+/// // can use "UTC" if chrono-tz feature is enabled, here use offset based
timezone
+/// let data_type = DataType::Timestamp(TimeUnit::Second, None);
+/// let a = Int64Array::from(vec![1_000_000_000, 2_000_000_000,
3_000_000_000]);
+/// let b = cast(&a, &data_type).unwrap();
+/// let b = b.as_primitive::<TimestampSecondType>(); // downcast to result type
+/// assert_eq!(2_000_000_000, b.value(1)); // values are the same as the type
has no timezone
+/// // use display to show them (note has no trailing Z)
+/// assert_eq!("2033-05-18T03:33:20", display::array_value_to_string(&b,
1).unwrap());
+/// ```
+///
+/// ## Casting timestamps to a timestamp with timezone
+///
+/// Similarly to the previous example, if you cast numeric values to a
timestamp
+/// with timezone, the cast kernel will not change the underlying values
+/// but display and othe functions will interpret them as being in the
provided timezone.
Review Comment:
other functions
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