Add excel export

Author: mayagbarnes

README.md

@@ -102,7 +102,7 @@ Returns a `PivotTableResult` dict containing the current `config` state.
 | `on_config_change` | `Callable[[], None] \| None` | `None` | Called when the user changes the pivot config interactively, including toolbar and header-menu actions. |
 | `enable_drilldown` | `bool` | `True` | Show an inline drill-down panel with source records when a cell is clicked. |
 | `locked` | `bool` | `False` | Viewer mode with exploration enabled. Toolbar config controls are read-only, viewer-safe actions like data export and group expand/collapse remain available, and header-menu sorting/filtering/`Show Values As` plus drill-down still work. |
-| `export_filename` | `str \| None` | `None` | Base filename (without extension) for exported files. Date and extension are appended automatically. Defaults to `"pivot-table"`. |
+| `export_filename` | `str \| None` | `None` | Base filename (without extension) for exported files (.xlsx, .csv, .tsv). Date and extension are appended automatically. Defaults to `"pivot-table"`. |
 
 > **Frontend-only interactions:** Column resize (drag header edges) and fullscreen mode (toolbar expand icon) are available automatically when `interactive=True`. No additional Python parameters are needed.
 
@@ -431,11 +431,13 @@ Hover over a parent column header to reveal the collapse toggle.
 
 ### Data Export
 
-Export the pivot table as CSV, TSV, or copy to clipboard. Available via the toolbar utility menu (download icon) whenever the interactive toolbar is shown, including locked viewer mode.
+Export the pivot table as Excel, CSV, TSV, or copy to clipboard. Available via the toolbar utility menu (download icon) whenever the interactive toolbar is shown, including locked viewer mode.
 
-- **Format**: CSV, TSV, or Clipboard (tab-separated for pasting into spreadsheets)
+- **Format**: Excel (.xlsx), CSV, TSV, or Clipboard (tab-separated for pasting into spreadsheets)
 - **Content**: Formatted (display values with currency, percentages, etc.) or Raw (unformatted numbers)
-- **Filename**: Customizable via `export_filename`. The date (`YYYY-MM-DD`) and file extension are appended automatically. Defaults to `"pivot-table"` (e.g. `pivot-table_2026-03-09.csv`).
+- **Filename**: Customizable via `export_filename`. The date (`YYYY-MM-DD`) and file extension are appended automatically. Defaults to `"pivot-table"` (e.g. `pivot-table_2026-03-09.xlsx`).
+
+Excel export produces a professionally styled workbook with merged column headers, bold totals/subtotals, number formatting, banded rows, frozen panes (headers stay visible when scrolling), and row dimension merging that matches the rendered table layout. Sort order, active filters, and show-values-as percentages are all preserved.
 
 Export always outputs the full expanded table regardless of any collapsed row/column groups.
 
@@ -513,7 +515,7 @@ When `interactive=True`, hovering over the top-right of the toolbar reveals util
 | **Swap** | Transposes row and column dimensions |
 | **Copy Config** | Copies the current config as JSON to clipboard |
 | **Import Config** | Paste a JSON config to apply |
-| **Export Data** | Open the export popover (CSV / TSV / Clipboard). Use `export_filename` to customize the download filename. |
+| **Export Data** | Open the export popover (Excel / CSV / TSV / Clipboard). Use `export_filename` to customize the download filename. |
 | **Fullscreen** (expand icon) | Toggles fullscreen mode — the table fills the entire viewport. Press Escape or click the collapse icon to exit. |
 | **Settings** (gear icon) | Opens a popover with display toggles: Row Totals, Column Totals, Subtotals, Repeat Labels, Sticky Headers, and Expand/Collapse All group controls |
 

e2e_playwright/pivot_table_data_test.py

@@ -133,6 +133,7 @@ def test_export_data_panel_opens(page_at_app: Page):
     panel = page.get_by_test_id("toolbar-export-data-panel")
     expect(panel).to_be_visible(timeout=5000)
 
+    expect(panel.get_by_test_id("export-format-xlsx")).to_be_visible()
     expect(panel.get_by_test_id("export-format-csv")).to_be_visible()
     expect(panel.get_by_test_id("export-format-tsv")).to_be_visible()
     expect(panel.get_by_test_id("export-content-formatted")).to_be_visible()
@@ -312,6 +313,33 @@ def test_csv_download_content(page_at_app: Page):
     assert len(content.strip().splitlines()) > 1, "CSV should have data rows"
 
 
+def test_excel_download_content(page_at_app: Page):
+    """Downloading Excel produces a .xlsx file with the expected filename."""
+    page = page_at_app
+    container = get_pivot(page, "test_pivot")
+    expect(container.get_by_test_id("pivot-toolbar")).to_be_visible(timeout=15000)
+
+    container.get_by_test_id("toolbar-export-data").evaluate("el => el.click()")
+    panel = page.get_by_test_id("toolbar-export-data-panel")
+    expect(panel).to_be_visible(timeout=5000)
+
+    # Excel is the default format; just select raw content
+    panel.get_by_test_id("export-content-raw").click()
+
+    with page.expect_download() as dl_info:
+        panel.get_by_test_id("toolbar-export-data-action").click()
+
+    download = dl_info.value
+    suggested = download.suggested_filename
+    assert suggested.endswith(".xlsx"), f"Expected .xlsx extension, got: {suggested}"
+
+    path = download.path()
+    assert path is not None
+
+    file_size = Path(path).stat().st_size
+    assert file_size > 100, f"Excel file too small ({file_size} bytes), likely empty"
+
+
 def test_sticky_headers_during_scroll(page_at_app: Page):
     """Sticky headers remain visible during vertical scroll."""
     page = page_at_app

streamlit_app.py

@@ -60,7 +60,7 @@
   - **Swap** (↔) — transposes row and column dimensions.
   - **Copy Config** — copies the current config as JSON to your clipboard.
   - **Import Config** — paste a JSON config to apply it.
-  - **Export Data** (↓) — export the table as CSV, TSV, or copy to clipboard
+  - **Export Data** (↓) — export the table as Excel, CSV, TSV, or copy to clipboard
     (see Section 11 for details).
   - **Settings** (⚙) — opens a popover with display toggles (e.g. Row Totals,
     Column Totals). More options appear here as you add features — see
@@ -812,13 +812,17 @@
 
 st.markdown(
     """
-Export the pivot table data as **CSV**, **TSV**, or copy to **clipboard** for
-pasting into Excel or Google Sheets.
+Export the pivot table data as **Excel** (.xlsx), **CSV**, **TSV**, or copy to
+**clipboard** for pasting into spreadsheets.
+
+Excel export produces a professionally styled workbook with merged column
+headers, bold totals/subtotals, number formatting, banded rows, and frozen
+panes — matching the quality you'd expect from BI tools like Sigma.
 
 **Try it:**
 - Use the top-right utility menu in the toolbar.
 - Click the **Download** icon (↓) to open the export popover.
-- Choose a **Format**: CSV, TSV, or Clipboard.
+- Choose a **Format**: Excel, CSV, TSV, or Clipboard.
 - Choose **Content**: Formatted (display values including currency, percentages)
   or Raw (unformatted aggregated numbers).
 - Click **Export** (downloads a file) or **Copy** (copies to clipboard as
@@ -828,7 +832,7 @@
 - Export is always available when the toolbar is visible (``interactive=True``).
 - Use ``export_filename`` to customize the downloaded file name. The date
   (``YYYY-MM-DD``) and file extension are appended automatically.
-  Defaults to ``"pivot-table"`` (e.g. ``pivot-table_2026-03-09.csv``).
+  Defaults to ``"pivot-table"`` (e.g. ``pivot-table_2026-03-09.xlsx``).
 - This demo sets `export_filename="sales-export-demo"` so you can see the custom
   filename behavior in the downloaded file.
 """

streamlit_pivot/__init__.py

@@ -729,9 +729,9 @@ def st_pivot_table(
         drill-down panel below the pivot table showing the
         contributing source records. Set to False to disable.
     export_filename : str or None
-        Base filename (without extension) used when exporting data.
-        The date and file extension are appended automatically.
-        Defaults to ``"pivot-table"`` when not set.
+        Base filename (without extension) used when exporting data
+        (.xlsx, .csv, .tsv). The date and file extension are appended
+        automatically. Defaults to ``"pivot-table"`` when not set.
     execution_mode : str
         Performance execution mode. ``"auto"`` (default) keeps the client-side
         path unless the dataset is large enough to trigger the threshold_hybrid