How to iterate over an Excel file and ID colored cell values - openpyxl

Question

I have an excel workbook that has cells of a column colored with specific colors to keep or exclude certain users that will then be used to filter another excel workbook.
I want to loop through this column and identify cells with red background and add a functional column stating 0 and identify cells with yellow background and add 1 to this same functional column so as to work as the filter for the other workbook.
I'm hoping to use OpenPyXL to complete this task.
column_pi = ws["A"]
for cell in column_pi:
f cell.fill.fgColor == "00FF0000": # Red Hex
# add column stating 0 as value
Have also tried this but no luck, returning nothing
red_fill = PatternFill(fill_type=None, start_color='00FF0000', end_color='00FF0000')
yellow_fill = PatternFill(fill_type=None, start_color='00FFFF00', end_color='00FFFF00')
for cell in column_pi:
if cell.fill == yellow_fill:
print(cell)
Works with no hex codes provided for no_fill
no_fill = PatternFill(fill_type=None)
for cell in column_pi:
if cell.fill == no_fill:
print(cell)
Any thoughts on the best way to iterate over the values and check the fill/background color are of a specific color and then add a functional column like this?

Answer 1

fill is a set of more complicated variables, so looking for it to be exactly equal only to red_fill or yellow_fill here isn't going to work. The complication is mostly due to being able to set a colour either as a static rgba value, or as one that will automatically update when the theme is changed. Styles in openpyxl, with parameters like PatternFill, are easy ways to set multiple of these values at once.
If you look up cell.fill for a particular cell, it returns something like:
<openpyxl.styles.fills.PatternFill object>
Parameters:
patternType='solid', fgColor=<openpyxl.styles.colors.Color object>
Parameters:
rgb='FFD9D9D9', indexed=None, auto=None, theme=None, tint=0.0, type='rgb', bgColor=<openpyxl.styles.colors.Color object>
Parameters:
rgb='00000000', indexed=None, auto=None, theme=None, tint=0.0, type='rgb'
You can specify these values directly as part of cell.fill.fill_type (synonym for cell.fill.patternType), cell.fill.fgColor, and cell.fill.bgColor. Plus sub-attributes like cell.fill.fgColor.rgb.
You could also make it quicker by picking knowncell.fill.fgColor of a cell you know to have red_fill, if one exists. That way, you could check any of fill_type, fgColor and/or bgColor match. Try:
red_fill = knowncell.fill
for cell in column_pi:
if cell.fill.fgColor == red_fill.fgColor and cell.fill.fill_type == red_fill.fill_type:
print(cell)
However, you can't match knowncell.fill directly with cell.fill, I think because a new openpyxl style object is created each time you define a new one.