#######################################################################
#
# An example of creating an Excel Line chart with a secondary axis
# using Python and XlsxWriter.
#
# Copyright 2013-2015, John McNamara, jmcnamara@cpan.org
#
import xlsxwriter

workbook = xlsxwriter.Workbook('chart_secondary_axis.xlsx')
worksheet = workbook.add_worksheet()
bold = workbook.add_format({'bold': 1})

# Add the worksheet data that the charts will refer to.
headings = ['Aliens', 'Humans']
data = [
    [2, 3, 4, 5, 6, 7],
    [10, 40, 50, 20, 10, 50],
]

worksheet.write_row('A1', headings, bold)
worksheet.write_column('A2', data[0])
worksheet.write_column('B2', data[1])


# Create a new chart object. In this case an embedded chart.
chart = workbook.add_chart({'type': 'line'})

# Configure a series with a secondary axis
chart.add_series({
    'name':   '=Sheet1!$A$1',
    'values': '=Sheet1!$A$2:$A$7',
    'y2_axis': 1,
})

chart.add_series({
    'name':   '=Sheet1!$B$1',
    'values': '=Sheet1!$B$2:$B$7',
})

chart.set_legend({'position': 'right'})

# Add a chart title and some axis labels.
chart.set_title({'name': 'Survey results'})
chart.set_x_axis({'name': 'Days', })
chart.set_y_axis({'name': 'Population', 'major_gridlines': {'visible': 0}})
chart.set_y2_axis({'name': 'Laser wounds'})

# Insert the chart into the worksheet (with an offset).
worksheet.insert_chart('D2', chart, {'x_offset': 25, 'y_offset': 10})

workbook.close()
