Dash Table export formated excel file

Hi,
This example script for dash table"

import dash
from dash.dependencies import Output, Input
import dash_html_components as html
import dash_core_components as dcc
import pandas as pd

app = dash.Dash(__name__)
app.layout = html.Div([
    html.Button("Download Excel", id="btn_xlsx"),
    dcc.Download(id="download-dataframe-xlsx"),
])


df = pd.DataFrame({"a": [1, 2, 3, 4], "b": [2, 1, 5, 6], "c": ["x", "x", "y", "y"]})


@app.callback(
    Output("download-dataframe-xlsx", "data"),
    Input("btn_xlsx", "n_clicks"),
    prevent_initial_call=True,
)
def func(n_clicks):
    return dcc.send_data_frame(df.to_excel, "mydf.xlsx", sheet_name="Sheet_name_1")


if __name__ == "__main__":
    app.run_server(debug=True)

This script how to export formatted excel file from pandas dataframe:

"""
Show examples of modifying the Excel output generated by pandas
"""
import pandas as pd
import numpy as np

from xlsxwriter.utility import xl_rowcol_to_cell


df = pd.read_excel("../in/excel-comp-datav2.xlsx")

# We need the number of rows in order to place the totals
number_rows = len(df.index)

# Add some summary data using the new assign functionality in pandas 0.16
df = df.assign(total=(df['Jan'] + df['Feb'] + df['Mar']))
df = df.assign(quota_pct=(1+(df['total'] - df['quota'])/df['quota']))

# Create a Pandas Excel writer using XlsxWriter as the engine.
# Save the unformatted results
writer_orig = pd.ExcelWriter('simple.xlsx', engine='xlsxwriter')
df.to_excel(writer_orig, index=False, sheet_name='report')
writer_orig.save()

# Create a Pandas Excel writer using XlsxWriter as the engine.
writer = pd.ExcelWriter('fancy.xlsx', engine='xlsxwriter')
df.to_excel(writer, index=False, sheet_name='report')

# Get access to the workbook and sheet
workbook = writer.book
worksheet = writer.sheets['report']

# Reduce the zoom a little
worksheet.set_zoom(90)

# Add a number format for cells with money.
money_fmt = workbook.add_format({'num_format': '$#,##0', 'bold': True})

# Add a percent format with 1 decimal point
percent_fmt = workbook.add_format({'num_format': '0.0%', 'bold': True})

# Total formatting
total_fmt = workbook.add_format({'align': 'right', 'num_format': '$#,##0',
                                 'bold': True, 'bottom':6})
# Total percent format
total_percent_fmt = workbook.add_format({'align': 'right', 'num_format': '0.0%',
                                         'bold': True, 'bottom':6})

# Format the columns by width and include number formats

# Account info columns
worksheet.set_column('B:D', 20)
# State column
worksheet.set_column('E:E', 5)
# Post code
worksheet.set_column('F:F', 10)

# Monthly columns
worksheet.set_column('G:K', 12, money_fmt)
# Quota percent columns
worksheet.set_column('L:L', 12, percent_fmt)

# Add total rows
for column in range(6, 11):
    # Determine where we will place the formula
    cell_location = xl_rowcol_to_cell(number_rows+1, column)
    # Get the range to use for the sum formula
    start_range = xl_rowcol_to_cell(1, column)
    end_range = xl_rowcol_to_cell(number_rows, column)
    # Construct and write the formula
    formula = "=SUM({:s}:{:s})".format(start_range, end_range)
    worksheet.write_formula(cell_location, formula, total_fmt)

# Add a total label
worksheet.write_string(number_rows+1, 5, "Total",total_fmt)
percent_formula = "=1+(K{0}-G{0})/G{0}".format(number_rows+2)
worksheet.write_formula(number_rows+1, 11, percent_formula, total_percent_fmt)

# Define our range for the color formatting
color_range = "L2:L{}".format(number_rows+1)

# Add a format. Light red fill with dark red text.
format1 = workbook.add_format({'bg_color': '#FFC7CE',
                               'font_color': '#9C0006'})

# Add a format. Green fill with dark green text.
format2 = workbook.add_format({'bg_color': '#C6EFCE',
                               'font_color': '#006100'})

# Highlight the top 5 values in Green
worksheet.conditional_format(color_range, {'type': 'top',
                                           'value': '5',
                                           'format': format2})

# Highlight the bottom 5 values in Red
worksheet.conditional_format(color_range, {'type': 'bottom',
                                           'value': '5',
                                           'format': format1})

writer.save()

Is there any way to export formatted excel files from the dash table?

1 Like

I have the same question!

Hello @KingClue1,

I believe that you can do this, by transferring the file that you created that was formatted.

As long as you know how you want the table to be formatted, you format it and then just transfer the file back with send_bytes.

Ok, is there a way I can export as XLSX a dash table that has cells colored in (like a heatmap)?

I will be generating a dataframe, making it into a dash-table and then applying heatmap coloring over it, I want to be able to download the table with itโ€™s styling (not just the numbers). Is there a way?

Or must I convert the dataframe into XLSX using some python library and apply the coloring there, then use send_bytes as you mentioned?

Not sure about being able to take it straight from the html, for dash, itโ€™d have to be created with the way you described as an excel file.

But, with an excel file you can apply the same conditional formatting, or even create a template to use and just insert the info. :stuck_out_tongue_winking_eye:

1 Like