如何使用XlsxWriter根据另一个工作表中的相应单元格值来格式化一个工作表中的所有单元格？

Question

I am exporting to Excel two pandas DataFrames using XlsxWriter, each DataFrame having a separate sheet. I would like to apply a colour format to all the cells in one sheet based on values in another sheet, they correspond one-to-one based on column names and row numbers.

Example:

Sheet1

  A B C
1 1 3 1
2 0 4 2

Sheet2

  A B C
1 a d b
2 b a a

I would like to assign a colour format to all the cells in Sheet1 that have a value 'a' in Sheet2.

Answer 1

The first step is to work out the conditional format in Excel and then transfer it to XlsxWriter.

Something like the following should work:

import pandas as pd

# Create some Pandas dataframes from some data.
df1 = pd.DataFrame([[ 1,   3,   1 ], [ 0,   4,   2 ]])
df2 = pd.DataFrame([['a', 'd', 'b'], ['b', 'a', 'a']])

# Create a Pandas Excel writer using XlsxWriter as the engine.
writer = pd.ExcelWriter('pandas_xlsxwriter.xlsx', engine='xlsxwriter')

# Write each dataframe to a different worksheet.
df1.to_excel(writer, sheet_name='Sheet1', header=False, index=False)
df2.to_excel(writer, sheet_name='Sheet2', header=False, index=False)

# Get the xlsxwriter workbook and worksheet objects.
workbook  = writer.book
worksheet = writer.sheets['Sheet1']

# Create a format for the conditional format.
condition_format = workbook.add_format({'bg_color': '#C6EFCE',
                                        'font_color': '#006100'})

# Write a conditional format over a range.
worksheet.conditional_format('A1:C2', {'type': 'formula',
                                       'criteria': '=Sheet2!A1="a"', 
                                       'format': condition_format})

# Close the Pandas Excel writer and output the Excel file.
writer.save()

Output:

Note that Excel requires double quotes around the string in the formula =Sheet2!A1="a" and by using a relative cell reference ( A1 not the absolute value $A$1 ) the formula is applied individually to each cell in the range.

You can apply the conditional format to a range based on the dataframe like this:

# Write a conditional format over a range.
start_row = 0
start_col = 0
end_row = df1.shape[0] -1
end_col = df1.shape[1] -1

worksheet.conditional_format(start_row, start_col, end_row, end_col, 
                             {'type': 'formula',
                              'criteria': '=Sheet2!A1="a"', 
                              'format': condition_format})