Using Python Pandas to Write Data to Excel and Sorting Entries

When working with data in Python, it’s often necessary to write the data to an Excel file for analysis or further processing. The pandas library provides a convenient way to do this, but sometimes additional steps are required to manipulate the data before writing it to the Excel file.

In this article, we’ll explore how to use pandas to write data to an Excel file and sort entries in one of the sheets while leaving the other sheet unsorted.

Introduction to Pandas and Excel Writing

Pandas is a popular Python library for data manipulation and analysis. It provides data structures and functions for efficiently handling structured data, including tabular data such as spreadsheets and SQL tables.

The pandas library includes a convenient function for writing data to an Excel file: ExcelWriter. This function allows you to write data to one or more Excel sheets, depending on your needs.

To use the ExcelWriter function, you’ll need to import the pandas library and create an instance of the class. You can then pass the data to be written to the Excel file using the to_excel method.

Creating a Sample DataFrame

For this example, we’ll create a sample DataFrame with two columns: Layers and weights. The Layers column will contain some sample values, and the weights column will contain corresponding weights for each layer.

import pandas as pd

# Create a sample DataFrame
data = {'Layers': ['T1_max_pool', 'activation_9', 'sum_9', 'Merge_2', 'activation_2', 'T2_max_pool'],
        'weights': [4, 1, 3, 4, 1, 4]}
df = pd.DataFrame(data)

Writing Data to an Excel File

To write the data to an Excel file using the ExcelWriter function, we can create an instance of the class and pass the DataFrame to be written using the to_excel method.

# Create an ExcelWriter object
writer = pd.ExcelWriter('file.xlsx')

# Write the data to the Excel file
df.to_excel(writer, 'sheet1')

Sorting Entries in One Sheet

To sort the entries in one sheet while leaving the other sheet unsorted, we can use the sort_values function on the Layers column. This will sort the values in ascending order by default.

We’ll create a new DataFrame that includes only the columns we’re interested in: Layers and weights. We’ll then pass this DataFrame to the ExcelWriter object using the to_excel method, specifying the sheet name as 'sheet2'.

# Sort the entries in one sheet
df_sorted = df.sort_values(by='Layers', ascending=True)

# Write the sorted data to an Excel file
df_sorted.to_excel(writer, 'sheet2')

Writing Data to Multiple Sheets

To write data to multiple sheets, we can create multiple instances of the ExcelWriter class and pass each DataFrame to the corresponding sheet name.

Here’s an example:

# Create multiple instances of the ExcelWriter class
writer = pd.ExcelWriter('file.xlsx')

# Write data to one sheet
df.to_excel(writer, 'sheet1')

# Sort the entries in another sheet
df_sorted = df.sort_values(by='Layers', ascending=True)
df_sorted.to_excel(writer, 'sheet2')

Using Index and Start Column

When writing data to an Excel file using the ExcelWriter function, you can specify the index as False or True, depending on your needs.

Here’s an example:

# Write data with no index
df.to_excel(writer, 'sheet1', index=False)

Alternatively, you can specify a start column for writing to the Excel file. Here’s an example:

# Write data starting from column 3
df.to_excel(writer, 'sheet2', startcol=3)

Conclusion

In this article, we’ve explored how to use pandas to write data to an Excel file and sort entries in one of the sheets while leaving the other sheet unsorted. We’ve covered topics such as creating a sample DataFrame, writing data to an Excel file, sorting entries in one sheet, writing data to multiple sheets, and using index and start column.

By following these steps and tips, you can efficiently write data to an Excel file using pandas and manipulate it to suit your needs.

Last modified on 2025-03-26