Conditional Formatting API

pyopenxlsx supports conditional formatting rules (color scales, data bars, cell comparisons, formulas, icon sets, and more). Prefer builders in pyopenxlsx.conditional_formatting for concise call sites; native XL* factories remain available.

High-level builders (recommended)

from pyopenxlsx import Workbook, conditional_formatting as cf

with Workbook() as wb:
    ws = wb.active
    ws.write_rows(1, [[1, 2, 3], [4, 5, 6], [7, 8, 9]])

    # Hex or RGB tuples
    ws.add_conditional_formatting("A1:C1", cf.color_scale("#FF0000", "#00FF00"))
    ws.add_conditional_formatting("A2:C2", cf.data_bar((0, 0, 255), show_value=True))
    ws.add_conditional_formatting("A3:C3", cf.cell_is(">", "5"))
    ws.add_conditional_formatting("A1:C3", cf.formula_rule("A1>5"))
    ws.add_conditional_formatting("A1:C3", cf.top10(3))
    ws.add_conditional_formatting("A1:C3", cf.icon_set("3TrafficLights1"))

    wb.save("conditional_formatting.xlsx")

Builder functions

Function	Description
`color_scale(start, end, mid=None)`	2- or 3-stop colour scale
`data_bar(color, *, show_value=True)`	Data bars
`cell_is(operator, formula, formula2=None)`	Comparison (`">"`, `">="`, `"between"`, … or `XLCfOperator`)
`formula_rule(formula)`	Expression rule
`icon_set` / `top10` / `above_average`	Rank and icon rules
`contains_text` / `duplicate_values` / blanks / errors	Text and uniqueness rules

Native rules

from pyopenxlsx._openxlsx import XLColorScaleRule, XLDataBarRule, XLColor

scale = XLColorScaleRule(XLColor(255, 0, 0), XLColor(0, 255, 0))
ws.add_conditional_formatting("A1:C1", scale)
bar = XLDataBarRule(XLColor(0, 0, 255), show_value=True)
ws.add_conditional_formatting("A2:C2", bar)

Managing rules

ws.add_conditional_formatting(sqref, rule)
ws.remove_conditional_formatting(sqref)
ws.clear_all_conditional_formatting()