如何根据openpyxl中的值（负值或正值）更改图表颜色？

Question

基于在openpyxl值（负或正值）如何更改图表的颜色？
真的很难为我。

from openpyxl import Workbook 
from openpyxl.styles import Border, Side, PatternFill, Font, GradientFill,Alignment, Color, numbers 
from openpyxl.chart import BarChart, Reference 

book = Workbook() 
sheet = book.active 
rows = [ 
['Number', 'Batch 1'], 
['a', 40], 
['b', -40], 
['c', 50], 
['d', -30], 
['e', -25], 
['f', 30], 
] 

for row in rows: 
    sheet.append(row) 

chart = BarChart() 
chartCats = Reference(sheet, min_col=1, min_row=2, max_row=7) 
chartData = Reference(sheet, min_col=2, min_row=1, max_col=2, max_row=7) 
chart.add_data(chartData, titles_from_data = True) 
chart.set_categories(chartCats) 
chart.type = 'bar' 
chart.style = 27 
chart.height = 10 
chart.width = 15 
chart.legend = None 
chart.x_axis.tickLblPos = "low" 
chart.y_axis.number_format = '#,##0' 
chart.y_axis.majorGridlines = None 
sheet.add_chart(chart, 'A1') 
book.save('test.xlsx') 

上面的代码创建标题为“Batch1”的图表。但我想要“Batch2”，其中负值和正值显示不同的颜色。

Answer 1

这目前无法与openpyxl来完成。按照https://www.extendoffice.com/documents/excel/2218-excel-chart-negative-values-different-color.html的说明，我在Excel中创建了一个图表，并将差异格式应用于数据系列。虽然openpyxl确实支持系列invertIfNegative属性，原来的OOXML规范不允许其他颜色的数据系列。这是通过对原始规范的扩展来完成的。