matplotlib分组条颜色变化

import matplotlib.pyplot as plt
import numpy as np

# 创建数据
categories = ['A', 'B', 'C', 'D']
group_names = ['Group 1', 'Group 2', 'Group 3']
data = np.random.rand(len(group_names), len(categories))

# 设置颜色映射
cmap = plt.get_cmap('viridis')

# 创建图形和坐标轴
fig, ax = plt.subplots()

# 绘制分组条
bar_width = 0.2
for i, group_data in enumerate(data):
    x = np.arange(len(categories)) + i * bar_width
    color = cmap(i / len(group_names))
    ax.bar(x, group_data, bar_width, label=group_names[i], color=color)

# 设置图例和标签
ax.set_xticks(np.arange(len(categories)) + bar_width * (len(group_names) - 1) / 2)
ax.set_xticklabels(categories)
ax.legend()

# 显示图形
plt.show()