# Adding a second axis

Adding a second axis actually involves creating a second chart that shares a common x-axis with the first chart but has a separate y-axis.

    from openpyxl import Workbook
    from openpyxl.chart import (
        LineChart,
        BarChart,
        Reference,
        Series,
    )

    wb = Workbook()
    ws = wb.active

    rows = [
        ['Aliens', 2, 3, 4, 5, 6, 7],
        ['Humans', 10, 40, 50, 20, 10, 50],
    ]

    for row in rows:
        ws.append(row)

    c1 = BarChart()
    v1 = Reference(ws, min_col=1, min_row=1, max_col=7)
    c1.add_data(v1, titles_from_data=True, from_rows=True)

    c1.x_axis.title = 'Days'
    c1.y_axis.title = 'Aliens'
    c1.y_axis.majorGridlines = None
    c1.title = 'Survey results'

    # Create a second chart
    c2 = LineChart()
    v2 = Reference(ws, min_col=1, min_row=2, max_col=7)
    c2.add_data(v2, titles_from_data=True, from_rows=True)
    c2.y_axis.axId = 200
    c2.y_axis.title = "Humans"

    # Display y-axis of the second chart on the right by setting it to cross the x-axis at its maximum
    c1.y_axis.crosses = "max"
    c1 += c2

    ws.add_chart(c1, "D4")

    wb.save("secondary.xlsx")

This produces a combined line and bar chart looking something like this: