How to save a new sheet in an existing excel file, using Pandas?

Thank you. I believe that a complete example could be good for anyone else who have the same issue:

import pandas as pd
import numpy as np

path = r"C:\Users\fedel\Desktop\excelData\PhD_data.xlsx"

x1 = np.random.randn(100, 2)
df1 = pd.DataFrame(x1)

x2 = np.random.randn(100, 2)
df2 = pd.DataFrame(x2)

writer = pd.ExcelWriter(path, engine="xlsxwriter")
df1.to_excel(writer, sheet_name="x1")
df2.to_excel(writer, sheet_name="x2")
writer.save()
writer.close()

Here I generate an excel file, from my understanding it does not really matter whether it is generated via the “xslxwriter” or the “openpyxl” engine.

When I want to write without loosing the original data then

import pandas as pd
import numpy as np
from openpyxl import load_workbook

path = r"C:\Users\fedel\Desktop\excelData\PhD_data.xlsx"

book = load_workbook(path)
writer = pd.ExcelWriter(path, engine="openpyxl")
writer.book = book

x3 = np.random.randn(100, 2)
df3 = pd.DataFrame(x3)

x4 = np.random.randn(100, 2)
df4 = pd.DataFrame(x4)

df3.to_excel(writer, sheet_name="x3")
df4.to_excel(writer, sheet_name="x4")
writer.save()
writer.close()

this code do the job!