.. _tutorial1:

Tutorial 1: Create a simple XLSX file
=====================================

.. highlight:: python

Let's start by creating a simple spreadsheet using Python and the XlsxWriter
module.

Say that we have some data on monthly outgoings that we want to convert into an
Excel XLSX file::

    expenses = (
        ['Rent', 1000],
        ['Gas',   100],
        ['Food',  300],
        ['Gym',    50],
    )

To do that we can start with a small program like the following:

.. code-block:: python

    from xlsxwriter.workbook import Workbook

    # Create a workbook and add a worksheet.
    workbook = Workbook('Expenses01.xlsx')
    worksheet = workbook.add_worksheet()
    
    # Some data we want to write to the worksheet.
    expenses = (
        ['Rent', 1000],
        ['Gas',   100],
        ['Food',  300],
        ['Gym',    50],
    )
    
    # Start from the first cell. Rows and columns are zero indexed. 
    row = 0
    col = 0
    
    # Iterate over the data and write it out row by row.
    for item, cost in (expenses):
        worksheet.write(row, col,     item)
        worksheet.write(row, col + 1, cost)
        row += 1
    
    # Write a total using a formula.
    worksheet.write(row, 0, 'Total')
    worksheet.write(row, 1, '=SUM(B1:B4)')
    
    workbook.close()

If we run this program we should get a spreadsheet that looks like this:

.. image:: _static/tutorial01.png

This is a simple example but the steps involved are representative of all
programs that use XlsxWriter, so let's break it down into separate parts.

The first step is to import the module and the main method that we will call::

    from xlsxwriter.workbook import Workbook

The next step is to create a new workbook object using the ``Workbook()``
constructor.

:func:`Workbook` takes one, non-optional, argument which is the filename that
we want to create::

    workbook = Workbook('Expenses01.xlsx')

.. note::
   XlsxWriter can only create *new files*. It cannot read or modify existing 
   files.

The workbook object is then used to add a new worksheet via the
:func:`add_worksheet` method::

    worksheet = workbook.add_worksheet()

By default worksheet names in the spreadsheet will be `Sheet1`, `Sheet2` etc.,
but we can also specify a name::

    worksheet1 = workbook.add_worksheet()        # Defaults to Sheet1.
    worksheet2 = workbook.add_worksheet('Data')  # Data.
    worksheet3 = workbook.add_worksheet()        # Defaults to Sheet3.

We can then use the worksheet object to write data via the :func:`write`
method::

    worksheet.write(row, col, some_data)

.. Note::   
   Throughout XlsxWriter, *rows* and *columns* are zero indexed. The
   first cell in a worksheet, ``A1``, is ``(0, 0)``.

So in our example we iterate over our data and write it out as follows::

    # Iterate over the data and write it out row by row.
    for item, cost in (expenses):
        worksheet.write(row, col,     item)
        worksheet.write(row, col + 1, cost)
        row += 1

We then add a formula to calculate the total of the items in the second column::

    worksheet.write(row, 1, '=SUM(B1:B4)')

Finally, we close the Excel file via the :func:`close` method::

    workbook.close()

Like most file objects in Python an XlsxWriter file is closed implicitly when
it goes out of scope or is no longer referenced in the program. As such this
line is generally optional unless you need to close the file explicitly.

And that's it. We now have a file that can be read by Excel and other
spreadsheet applications.

In the next sections we will see how we can use the XlsxWriter module to add
formatting and other Excel features.





