Python与Matplotlib问题：循环第二次后表格尺寸异常

我正在开发一款小型数字标牌应用，用Python+Matplotlib实现循环全屏显示数据柱状图及下方对应数据表格，实际应用中每次循环会从数据库拉取新数据（此功能已正常实现）。

问题表现：首次循环时柱状图与表格显示完全正常，但第二次及后续循环中，表格数据被压缩至约一半垂直空间，且旧视图仍可见。

原复现代码 #

import matplotlib.pyplot as plt
import matplotlib as mpl
import numpy as np
import pandas as pd

# 顶部显示较大柱状图，下方显示较小数据表格
fig, (ax, ax_table) = plt.subplots(nrows = 2, gridspec_kw = dict(height_ratios = [7,1]))

ax_table.axis('off') # 移除多余的图表坐标轴

mng = plt.get_current_fig_manager()
mng.full_screen_toggle() # 切换至全屏显示

while(True):
    test_data = [["A","B","A","B","A","B","A","B","A","B"], [1,2,3,4,5,6,7,8,9,10], [100,200,300,400,500,600,700,800,900,1000], [0.1,0.2,0.3,0.4,0.5,0.6,0.7,0.8,0.9,1.0]]
    
    dfcon = pd.DataFrame(test_data)
    dfcon = dfcon.transpose()
    print('dfcon = ')
    print(dfcon)
    
    ax.cla()    # 清除当前坐标轴（柱状图区域）
    ticks = np.arange(len(dfcon))
           
    bar_width = 0.4
    ax.set_xticks(ticks)
    ax.margins(x=0.01) # 按元素数量分配两侧边距，使柱状图与表格对齐
    b1 = ax.bar(ticks , dfcon[1], width= -(bar_width), align = 'edge') # 负宽度使柱状图对齐刻度左侧
    b2 = ax.bar(ticks , dfcon[3], width= bar_width, align = 'edge')
    
    ax.plot(kind='bar')
        
    ax.minorticks_on()
    ax.grid(which='major', linestyle='-', linewidth='0.5', color='green')
    ax.grid(which='minor', linestyle=':', linewidth='0.5', color='black')
    ax.set_ylabel('Time')
    
    descriptors = ('Tag', 'Target', 'Actual', 'Small #')
    ax_table = plt.table(cellText=test_data, rowLabels = descriptors, loc='center')
    ax_table.auto_set_font_size(False)
    ax_table.set_fontsize(12)
       
    fig.canvas.draw()
    fig.canvas.flush_events()
    fig.show()
    
    plt.pause(10)

我尝试过多种方法维持表格尺寸与位置，包括在循环内重新声明DataFrame、调用ax_table.clear()等，但未能解决表格未刷新反而重写并缩小的问题，部分操作还引发了错误。

修复后的可行代码 #

经调整后，核心修复点包括：

• 每次循环清除表格区域的坐标轴内容
• 重新关闭表格区域的坐标轴，避免多余元素干扰
• 使用bbox参数控制表格的尺寸范围，确保表格占满分配的空间
• 将表格添加到预先创建的ax_table坐标轴，而非覆盖坐标轴对象

import matplotlib.pyplot as plt
import matplotlib as mpl
import numpy as np
import pandas as pd

# 顶部显示较大柱状图，下方显示较小数据表格
fig, (ax, ax_table) = plt.subplots(nrows = 2, gridspec_kw = dict(height_ratios = [7,1]))

mng = plt.get_current_fig_manager()
mng.full_screen_toggle() # 切换至全屏显示

while(True):

    test_data = [["A","B","A","B","A","B","A","B","A","B"], [1,2,3,4,5,6,7,8,9,10], [100,200,300,400,500,600,700,800,900,1000], [0.1,0.2,0.3,0.4,0.5,0.6,0.7,0.8,0.9,1.0]]
    
    dfcon = pd.DataFrame(test_data)
    dfcon = dfcon.transpose()
    print('dfcon = ')
    print(dfcon)
    
    ax.cla()    # 清除当前坐标轴（柱状图区域）
    ax_table.cla() # 清除当前坐标轴（表格区域）
    ticks = np.arange(len(dfcon))
           
    bar_width = 0.4
    ax.set_xticks(ticks)
    ax.margins(x=0.01) # 按元素数量分配两侧边距，使柱状图与表格对齐
    b1 = ax.bar(ticks , dfcon[1], width= -(bar_width), align = 'edge') # 负宽度使柱状图对齐刻度左侧
    b2 = ax.bar(ticks , dfcon[3], width= bar_width, align = 'edge')
    
    ax.plot(kind='bar')
        
    ax.minorticks_on()
    ax.grid(which='major', linestyle='-', linewidth='0.5', color='green')
    ax.grid(which='minor', linestyle=':', linewidth='0.5', color='black')
    ax.set_ylabel('Time')
    
    descriptors = ('Tag', 'Target', 'Actual', 'Small #')

    ax_table.cla()
    ax_table.axis('off') # 移除多余的图表坐标轴
    
    # 创建新表格并添加至坐标轴
    tb = plt.table(cellText=test_data, rowLabels = descriptors, bbox = [0,0,1,1.5], loc='center') # 添加bbox确保表格尺寸正确
    tb.auto_set_font_size(False)
    tb.set_fontsize(12)
        
    ax_table.add_table(tb)
   
    fig.canvas.draw()
    fig.canvas.flush_events()
    fig.show()
    
    plt.pause(10)

内容的提问来源于stack exchange，提问作者Professor Barney