I desire to append dataframe to excel
This code works nearly as desire. Though it does not append each time. I run it and it puts data-frame in excel. But each time I run it it does not append. I also hear openpyxl is cpu intensive but not hear of many workarounds.
import pandas
from openpyxl import load_workbook
book = load_workbook('C:\\OCC.xlsx')
writer = pandas.ExcelWriter('C:\\OCC.xlsx', engine='openpyxl')
writer.book = book
writer.sheets = dict((ws.title, ws) for ws in book.worksheets)
df1.to_excel(writer, index = False)
writer.save()
I want the data to append each time I run it, this is not happening.
Data output looks like original data:
A B C
H H H
I want after run a second time
A B C
H H H
H H H
Apologies if this is obvious I new to python and examples I practise did not work as wanted.
Question is - how can I append data each time I run. I try change to xlsxwriter but get AttributeError: 'Workbook' object has no attribute 'add_format'
first of all, this post is the first piece of the solution, where you should specify startrow=
:
Append existing excel sheet with new dataframe using python pandas
you might also consider header=False
.
so it should look like:
df1.to_excel(writer, startrow = 2,index = False, Header = False)
if you want it to automatically get to the end of the sheet and append your df then use:
startrow = writer.sheets['Sheet1'].max_row
and if you want it to go over all of the sheets in the workbook:
for sheetname in writer.sheets:
df1.to_excel(writer,sheet_name=sheetname, startrow=writer.sheets[sheetname].max_row, index = False,header= False)
btw: for the writer.sheets
you could use dictionary comprehension (I think it's more clean, but that's up to you, it produces the same output):
writer.sheets = {ws.title: ws for ws in book.worksheets}
so full code will be:
import pandas
from openpyxl import load_workbook
book = load_workbook('test.xlsx')
writer = pandas.ExcelWriter('test.xlsx', engine='openpyxl')
writer.book = book
writer.sheets = {ws.title: ws for ws in book.worksheets}
for sheetname in writer.sheets:
df1.to_excel(writer,sheet_name=sheetname, startrow=writer.sheets[sheetname].max_row, index = False,header= False)
writer.save()