如何使用 python 将多个数据帧写入 excel 并使用 streamlit 下载结果？

Question

I have a Python script using streamlit, that allows the user to upload certain excel files, then it automatically runs my anslysis on it, and then I want them to download the results in xlsx format using the streamlit download button. However, I know how to make them download one dataframe to a csv, but not an xlsx file using the streamlit download button, which is what I want to do.

Here's what I've tried so far, and this is after my analysis where I'm just trying to create the download button for the user to download the results that are stored in 3 different dataframes:

Import pandas as pd
Import streamlit as st

# arrived_clean, booked_grouped, and arrived_grouped are all dataframes that I want to export to an excel file as results for the user to download. 

def convert_df():
    writer = pd.ExcelWriter('test_data.xlsx', engine='xlsxwriter')
    arrived_clean.to_excel(writer, sheet_name='Cleaned', startrow=0, startcol=0, index=False)
    booked_grouped.to_excel(writer, sheet_name='Output', startrow=0, startcol=0, index=False)
    arrived_grouped.to_excel(writer, sheet_name='Output', startrow=0, startcol=20, index=False)
    writer.save()

csv = convert_df()

st.download_button(
     label="Download data",
     data=csv,
     file_name='test_data.xlsx',
     mime='text/xlsx',
 )

When I first run the streamlit app locally I get this error:

"NameError: name 'booked_grouped' is not defined"

I get it because I haven't uploaded any files yet. After I upload my files the error message goes away and everything runs normally. However, I get this error and I don't see the download button to download my new dataframes:

RuntimeError: Invalid binary data format: <class 'NoneType'> line 313, in marshall_file raise RuntimeError("Invalid binary data format: %s" % type(data))

Can someone tell me what I'm doing wrong? It's the last piece I have to figure out.

Answer 1

When I first run the streamlit app locally I get this error:

"NameError: name 'booked_grouped' is not defined"

Assuming your code

booked_grouped = st.fileuploader('Something.....`)

You can use the below method to skip the error

if booked_grouped:
    # All your code inside this indentation

To Download excel

Convert all dataframes to one single excel

# Function to save all dataframes to one single excel
def dfs_tabs(df_list, sheet_list, file_name):
    writer = pd.ExcelWriter(file_name,engine='xlsxwriter')   
    for dataframe, sheet in zip(df_list, sheet_list):
        dataframe.to_excel(writer, sheet_name=sheet, startrow=0 , startcol=0)   
    writer.save()

# list of dataframes 
dfs = [df, df1, df2]

# list of sheet names
sheets = ['df','df1','df2']    

# run function
dfs_tabs(dfs, sheets, 'multi-test.xlsx')

An excel file with 'multi-test.xlsx will be saved locally

st.download_button(
     label="Download data as Excel",
     data='multi-test.xlsx',
     file_name='multi-test.xlsx',
     mime='text/xlsx',
 )

If the above method doesn't work, try this

data = pd.read_excel('multi-test.xlsx')

st.download_button(
     label="Download data as Excel",
     data=data,
     file_name='multi-test.xlsx',
     mime='text/xlsx',
 )