pandas - Getting AttributeError 'Workbook' object has no attribute 'add_worksheet' - while writing data frame to excel sheet

Question

I have the following code, and I am trying to write a data frame into an "existing" worksheet of an Excel file (referred here as test.xlsx). Sheet3 is the targeted sheet where I want to place the data, and I don't want to replace the entire sheet with a new one.

df = pd.DataFrame({'Data': [10, 20, 30, 20, 15, 30, 45]})
book = load_workbook('test.xlsx')
writer = pd.ExcelWriter('test.xlsx')
writer.book = book
writer.sheets = dict((ws.title, ws) for ws in book.worksheets) # *I am not sure what is happening in this line*
df.to_excel(writer,"Sheet3",startcol=0, startrow=20)

When I am running the code line by line, I am getting this error for the last line:

AttributeError: 'Workbook' object has no attribute 'add_worksheet'. Now why am I seeing this error when I am not trying to add worksheet ?

Note: I am aware of this similar issue Python How to use ExcelWriter to write into an existing worksheet but its not working for me and I can't comment on that post either.

Answer 1

You can use the append_df_to_excel() helper function, which is defined in this answer:

Usage:

append_df_to_excel('test.xlsx', df, sheet_name="Sheet3", startcol=0, startrow=20)

Some details:

**to_excel_kwargs - used in order to pass additional named parameters to df.to_excel() like i did in the example above - parameter startcol is unknown to append_df_to_excel() so it will be treated as a part of **to_excel_kwargs parameter (dictionary).

writer.sheets = {ws.title:ws for ws in writer.book.worksheets} is used in order to copy existing sheets to writer openpyxl object. I can't explain why it's not done automatically when reading writer = pd.ExcelWriter(filename, engine='openpyxl') - you should ask authors of openpyxl module about that...