在 matplotlib.axes.Axes.table 中设置 alpha？

Question

我试图了解如何在 matplotlib 表中设置 alpha 级别。我尝试使用全局 rcParams 设置它，但不太确定该怎么做？ （我想更改标题颜色的透明度）。一般来说，我不确定这可以在全球范围内完成，如果不能，我如何将参数传递给表？提前谢谢。

import pandas as pd
import numpy as np
import matplotlib.pyplot as plt
from cycler import cycler
import six

# Set universal font and transparency
plt.rcParams["font.family"] = "DejaVu Sans"
plt.rcParams['axes.prop_cycle'] = cycler(alpha=[0.5])

raw_data = dict(Simulation=[42, 39, 86, 15, 23, 57],
                SP500=[52, 41, 79, 80, 34, 47],
                NASDAQ=[62, 37, 84, 51, 67, 32],
                Benchmark=[72, 43, 36, 26, 53, 88])

df = pd.DataFrame(raw_data, index=pd.Index(
    ['Sharpe Ratio', 'Sortino Ratio', 'Calmars Ratio', 'VaR', 'CVaR', 'Max DD'], name='Metric'),
                  columns=pd.Index(['Simulation', 'SP500', 'NASDAQ', 'Benchmark'], name='Series'))


def create_table(data, col_width=None, row_height=None, font_size=None,
                 header_color='#000080', row_colors=None, edge_color='w',
                 header_columns=0, ax=None, bbox=None):
    if row_colors is None:
        row_colors = ['#D8D8D8', 'w']
    if bbox is None:
        bbox = [0, 0, 1, 1]
    if ax is None:
        size = (np.array(data.shape[::-1]) + np.array([0, 1])) * np.array([col_width, row_height])
        fig, ax = plt.subplots(figsize=size)
        ax.axis('off')

    ax.axis([0, 1, data.shape[0], -1])

    data_table = ax.table(cellText=data.values, colLabels=data.columns, rowLabels=data.index,
                          bbox=bbox, cellLoc='center', rowLoc='left', colLoc='center',
                          colWidths=([col_width] * len(data.columns)))
    cell_map = data_table.get_celld()
    for i in range(0, len(data.columns)):
        cell_map[(0, i)].set_height(row_height * 0.20)

    data_table.auto_set_font_size(False)
    data_table.set_fontsize(font_size)

    for k, cell in six.iteritems(data_table._cells):
        cell.set_edgecolor(edge_color)
        if k[0] == 0 or k[1] < header_columns:
            cell.set_text_props(weight='bold', color='w')
            cell.set_facecolor(header_color)
        else:
            cell.set_facecolor(row_colors[k[0] % len(row_colors)])

    return ax


ax = create_table(df, col_width=1.5, row_height=0.5, font_size=8)

ax.set_title("Risk Measures", fontweight='bold')

ax.axis('off')

plt.tight_layout()

plt.savefig('risk_parameter_table[1].pdf')

plt.show()

Answer 1

您可以在桌子的_cells上手动set_alpha()。

如果您只想更改标题，请检查row == 0 或col == -1：

def create_table(...):
    ...

    for (row, col), cell in data_table._cells.items():
        if (row == 0) or (col == -1):
            cell.set_alpha(0.5)

    return ax