精确预分配按股行情分组

2026-09-07 13:57:12 +08:00
parent fbf5a6d61a
commit 9714c051c5
1 changed files with 8 additions and 2 deletions
@@ -4513,8 +4513,14 @@ fn group_rows_by_symbol_id<'a, T>(
    symbol_ids_by_date: &BTreeMap<NaiveDate, Vec<u32>>,
    symbol_count: usize,
 ) -> Result<Vec<Vec<&'a T>>, DataSetError> {
-    let mut rows_by_symbol_id = (0..symbol_count)
-        .map(|_| Vec::<&T>::new())
+    let mut row_counts_by_symbol_id = vec![0usize; symbol_count];
+    for symbol_id in symbol_ids_by_date.values().flatten() {
+        row_counts_by_symbol_id[*symbol_id as usize] =
+            row_counts_by_symbol_id[*symbol_id as usize].saturating_add(1);
+    }
+    let mut rows_by_symbol_id = row_counts_by_symbol_id
+        .into_iter()
+        .map(Vec::<&T>::with_capacity)
        .collect::<Vec<_>>();
    for (date, rows) in groups {
        let symbol_ids = symbol_ids_by_date