fix: take use_columns into account when loading a sheet eagerly (#260)

Signed-off-by: Luka Peschke <[email protected]>

python/tests/test_column_selection.py

@@ -477,3 +477,17 @@ def test_use_columns_with_bad_callable() -> None:
             2,
             use_columns=lambda _: 42,  # type: ignore
         )
+
+
+def test_use_columns_with_eager_loading() -> None:
+    excel_reader = fastexcel.read_excel(path_for_fixture("fixture-single-sheet.xlsx"))
+
+    # default
+    rb = excel_reader.load_sheet_eager(0)
+    assert rb.schema.names == ["Month", "Year"]
+    # changing order
+    rb = excel_reader.load_sheet_eager(0, use_columns=["Year", "Month"])
+    assert rb.schema.names == ["Year", "Month"]
+    # subset
+    rb = excel_reader.load_sheet_eager(0, use_columns=["Year"])
+    assert rb.schema.names == ["Year"]

src/types/python/excelreader.rs

@@ -136,7 +136,9 @@ impl ExcelReader {
             dtype_coercion,
         )?;
 
-        let fields = available_columns
+        let final_columns = selected_columns.select_columns(&available_columns)?;
+
+        let fields = final_columns
             .iter()
             .map(Into::<Field>::into)
             .collect::<Vec<_>>();