Executive dashboard

Combine a summary sheet with the detail sheets behind it

The pattern most requested for internal reporting: one clean summary that opens first, with the underlying detail on tabs behind it.

import os
import polars as pl
import jetxl as jet

summary = pl.DataFrame({
    "Quarter": ["Q1", "Q2", "Q3", "Q4"],
    "Revenue": [100000, 120000, 115000, 140000],
    "Target":  [95000, 110000, 120000, 135000],
})

detail = pl.DataFrame({
    "Date":    ["2026-01-05", "2026-01-12", "2026-01-19"],
    "Region":  ["North", "South", "East"],
    "Amount":  [12500.00, 8900.00, 21000.00],
})

sheets = [
    {
        "data": summary.to_arrow(),
        "name": "Summary",
        "styled_headers": True,
        "freeze_rows": 1,
        "auto_width": True,
        "gridlines_visible": False,
        "zoom_scale": 120,
        "tab_color": "0070C0",
        "default_row_height": 20.0,
        "column_formats": {"Revenue": "currency", "Target": "currency"},
        "charts": [{
            "chart_type": "column",
            "start_row": 1, "start_col": 0,
            "end_row": 1 + summary.height, "end_col": 2,
            "from_col": 4,  "from_row": 1,
            "to_col": 12,   "to_row": 18,
            "title": "Revenue vs Target",
            "title_bold": True,
            "title_font_size": 1600,
            "title_color": "0070C0",
            "category_col": 0,
            "x_axis_title": "Quarter",
            "y_axis_title": "Amount ($)",
            "legend_position": "bottom",
            "axis_min": 0.0,
        }],
    },
    {
        "data": detail.to_arrow(),
        "name": "Detail",
        "styled_headers": True,
        "freeze_rows": 1,
        "auto_filter": True,
        "auto_width": True,
        "tab_color": "00B050",
        "column_formats": {"Amount": "currency", "Date": "date"},
        "conditional_formats": [{
            "start_row": 2, "start_col": 2,
            "end_row": 1 + detail.height, "end_col": 2,
            "rule_type": "color_scale",
            "min_color": "F8696B",
            "mid_color": "FFEB84",
            "max_color": "63BE7B",
        }],
    },
]

jet.write_sheets_arrow(
    sheets,
    "dashboard.xlsx",
    num_threads=min(os.cpu_count() or 1, len(sheets)),
)

Verified against jetxl 0.3.1: this produces a two-tab workbook, Summary then Detail, that opens cleanly.

What makes it read as a dashboard

Summary sheet comes first

Sheet order follows list order, and Excel opens on the first tab. Put the answer there and the working behind it.

Gridlines off, zoom up

Only on the summary. The detail sheet keeps its gridlines, because people scanning rows want them.

Tabs colored by role

Blue for the summary, green for detail. In a workbook of twelve tabs this is what makes it navigable.

Axis starts at zero

axis_min set to 0.0 on a column chart. Without it Excel may truncate the axis and exaggerate the gap between revenue and target.

Every range here is computed from summary.height or detail.height rather than hardcoded, so the workbook survives a change in row count. Use len(df) with Pandas.