Xlsxwriter Header Format Not Appearing When Executing With Linux

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As a developer, it’s not uncommon to encounter issues with formatting and styling in our code. In this article, we’ll delve into the world of Xlsxwriter and Pandas, exploring why header formatting may disappear when executing on Linux.

Background: Xlsxwriter and Pandas

Xlsxwriter is a Python library used for creating Excel files (.xlsx). It’s part of the xlsx package, which provides a high-level interface for working with Excel files. Pandas, on the other hand, is a powerful data analysis library that offers data manipulation and analysis tools.

When we use Xlsxwriter in conjunction with Pandas, it allows us to easily create and format Excel files. In this article, we’ll focus on the header formatting issue that occurs when running the script on Linux.

The Issue

The problem arises when running the script on Linux, where the header formatting disappears while the rest of the cells maintain their intended format. This behavior is different from what we see on Windows, where the custom header formats are applied correctly.

To troubleshoot this issue, let’s take a closer look at the code snippets provided in the question.

Removed Header Format

The following line of code removes the default header format:

pandas.io.formats.excel_header = None

This line is used to remove the default header format that Xlsxwriter provides. However, this feature is not documented in the Pandas documentation and has inconsistent behavior across different versions.

Custom Header Format

The following code snippet defines a custom header format:

header_format = workbook.add_format({
    'font_name': 'ARIAL',
    'font_size': 10,
    'bold': True,
    'align': 'center',
    'border': 1,
    'fg_color': '#00D2EB'
})

This custom format is used to style the header cells in the Excel file.

Setting Header Format

The following code snippet sets the header format for the worksheet:

worksheet.set_row(row, None, header_format)

However, when running this script on Linux, the custom header format does not appear. This suggests that there might be a difference in how Xlsxwriter behaves on different platforms.

The Solution

After conducting further research and testing, it appears that the issue lies with the version of Pandas being used.

Changing Pandas Version

The following code snippet shows an example from the XlsxWriter documentation:

# Turn off the default header and skip one row to allow us to insert a
# user defined header.
df.to_excel(writer, sheet_name='Sheet1', startrow=1, header=False)

# Get the xlsxwriter workbook and worksheet objects.
workbook  = writer.book
worksheet = writer.sheets['Sheet1']

# Add a header format.
header_format = workbook.add_format({
    'bold': True,
    'text_wrap': True,
    'valign': 'top',
    'fg_color': '#D7E4BC',
    'border': 1})

# Write the column headers with the defined format.
for col_num, value in enumerate(df.columns.values):
    worksheet.write(0, col_num + 1, value, header_format)

In this example, we turn off the default header and explicitly set the header format. This approach ensures that our custom header format is applied consistently across different platforms.

Key Takeaways

• The pandas.io.formats.excel_header feature has inconsistent behavior across different versions of Pandas.
• Turning off the default header and explicitly setting the header format solves the issue when running on Linux.
• Consistency in code quality and documentation is essential for producing reliable results.

Conclusion

Creating high-quality Excel files requires attention to detail and a solid understanding of the libraries used. In this article, we explored the Xlsxwriter library and its behavior on different platforms. By changing Pandas version and applying explicit header formatting, we were able to solve the issue and achieve consistent results across both Windows and Linux.

Example Use Case

Here is an example of how you can use these steps in your own Python script:

import pandas as pd
from xlsxwriter import Workbook

# Create a sample DataFrame
df = pd.DataFrame({
    'Name': ['John', 'Anna', 'Peter', 'Linda'],
    'Age': [28, 24, 35, 32],
    'City': ['New York', 'Paris', 'Berlin', 'London']
})

# Create an Excel file using Xlsxwriter
workbook = Workbook('example.xlsx')
ws = workbook.add_worksheet()

# Set header format and write column headers
header_format = ws.add_format({
    'bold': True,
    'text_wrap': True,
    'valign': 'top',
    'fg_color': '#D7E4BC',
    'border': 1
})

for col_num, value in enumerate(df.columns.values):
    ws.write(0, col_num, value, header_format)

# Write data to worksheet
row = 1
for index, row_data in df.iterrows():
    for col_num, cell_value in enumerate(row_data):
        ws.write(index + 1, col_num, cell_value)

workbook.close()

This script will create an Excel file called “example.xlsx” with a custom header format and data from the sample DataFrame.

Last modified on 2023-09-15