[GitHub] [arrow-rs] jorgecarleitao commented on a change in pull request #493: implement second/minute helpers for temporal

[GitBox <gi...@apache.org>]

jorgecarleitao commented on a change in pull request #493:
URL: https://github.com/apache/arrow-rs/pull/493#discussion_r656987963



##########
File path: arrow/src/compute/kernels/temporal.rs
##########
@@ -100,6 +100,72 @@ where
     Ok(b.finish())
 }
 
+/// Extracts the minutes of a given temporal array as an array of integers
+pub fn minute<T>(array: &PrimitiveArray<T>) -> Result<Int32Array>
+where
+    T: ArrowTemporalType + ArrowNumericType,
+    i64: std::convert::From<T::Native>,
+{
+    let mut b = Int32Builder::new(array.len());
+    match array.data_type() {
+        &DataType::Date64 | &DataType::Timestamp(_, _) => {
+            for i in 0..array.len() {
+                if array.is_null(i) {
+                    b.append_null()?;
+                } else {
+                    match array.value_as_datetime(i) {
+                        Some(dt) => b.append_value(dt.minute() as i32)?,
+                        None => b.append_null()?,
+                    }
+                }
+            }
+        }
+        dt => {
+            return {
+                Err(ArrowError::ComputeError(format!(
+                    "minute does not support type {:?}",
+                    dt
+                )))
+            }
+        }
+    }
+
+    Ok(b.finish())
+}
+
+/// Extracts the seconds of a given temporal array as an array of integers
+pub fn second<T>(array: &PrimitiveArray<T>) -> Result<Int32Array>
+where
+    T: ArrowTemporalType + ArrowNumericType,
+    i64: std::convert::From<T::Native>,
+{
+    let mut b = Int32Builder::new(array.len());
+    match array.data_type() {
+        &DataType::Date64 | &DataType::Timestamp(_, _) => {

Review comment:
       I am not sure this is correct: when the timestamp is timezone-aware can we extract the second from its corresponding timezone-unaware equivalent?




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