I recently needed to process some Excel files in Python. I used the xlrd library.
I needed to take special action if the background colour of a particular cell was solid cyan (RGB (0,255,255)).
Here is a function that determines if a particular cell from a given workbook has a solid cyan background. Note that the cell itself doesn’t contain its own formatting information - it has an “XF style” index, which points into a list of “XF Styles” held by the workbook.xf_list, which in turn points into tables of colours.
def cell_background_is_cyan ( workbook, cell ):
# Returns TRUE if the given cell from the given workbook has a solid cyan RGB (0,255,255) background.
# Note that the workbook must be opened with formatting_info = True, i.e.
# xlrd.open_workbook(xls_filename, formatting_info=True)
assert type (cell) is xlrd.sheet.Cell
assert type (workbook) is xlrd.book.Book
xf_index = cell.xf_index
xf_style = workbook.xf_list[xf_index]
xf_background = xf_style.background
fill_pattern = xf_background.fill_pattern
pattern_colour_index = xf_background.pattern_colour_index
background_colour_index = xf_background.background_colour_index
pattern_colour = workbook.colour_map[pattern_colour_index]
background_colour = workbook.colour_map[background_colour_index]
# If the cell has a solid cyan background, then:
# - fill_pattern will be 0x01
# - pattern_colour will be cyan (0,255,255)
# - background_colour is not used with fill pattern 0x01. (undefined value)
# So despite the name, for a solid fill, the background colour is not actually the background colour.
# Refer https://www.openoffice.org/sc/excelfileformat.pdf S. 2.5.12 'Patterns for Cell and Chart Background Area'
if fill_pattern == 0x01 and pattern_colour == (0,255,255):