python - Appending pandas dataframes generated in a for loop

Question

I am accessing a series of Excel files in a for loop. I then read the data in the excel file to a pandas dataframe. I cant figure out how to append these dataframes together to then save the dataframe (now containing the data from all the files) as a new Excel file.

Here's what I tried:

for infile in glob.glob("*.xlsx"):
    data = pandas.read_excel(infile)
    appended_data = pandas.DataFrame.append(data) # requires at least two arguments
appended_data.to_excel("appended.xlsx")

Thanks!

question from:https://stackoverflow.com/questions/65852800/how-can-i-combine-a-large-number-of-pandas-dataframes-more-quickly

Answer 1

Use pd.concat to merge a list of DataFrame into a single big DataFrame.

appended_data = []
for infile in glob.glob("*.xlsx"):
    data = pandas.read_excel(infile)
    # store DataFrame in list
    appended_data.append(data)
# see pd.concat documentation for more info
appended_data = pd.concat(appended_data)
# write DataFrame to an excel sheet 
appended_data.to_excel('appended.xlsx')