Matplotlib双轴图表添加数据标题及修复X轴整数显示问题

针对你的两个需求，以下是具体的修改方案：

1. 为两个数据系列添加对应轴标题 #

直接给两个坐标轴设置ylabel，分别对应"open"和"closed"：

• 给柱状图所在的ax_1添加Y轴标题：ax_1.set_ylabel('open')
• 给折线图所在的ax_2添加Y轴标题：ax_2.set_ylabel('closed')

2. 修复X轴显示小数的问题 #

通过强制指定X轴刻度为数据中的整数年份，解决自动生成小数刻度的问题：

• 添加ax_1.set_xticks(df['year'])，让X轴仅显示数据里的整数年份
• 可选补充：添加plt.xticks(rotation=45)，旋转刻度标签避免因年份过多导致重叠

修改后的完整代码 #

import pandas as pd
import matplotlib.pyplot as plt
from matplotlib.cm import get_cmap


data = {'year': [2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018, 2019, 2020, 2021, 2022, 2023],
        'open': [70, 20, 24, 150, 80, 90, 60, 90, 20, 20, 20, 24, 150, 80, 90, 60, 90, 20, 30],
        'closed':[30, 14, 20, 10, 20, 40, 10, 10, 10, 10, 30, 14, 20, 10, 20, 40, 10, 10, 10]}

df = pd.DataFrame(data, columns = ['year',
                                   'open',
                                   'closed'])


fig, ax_1 = plt.subplots(figsize = (8, 5))
ax_2 = ax_1.twinx()
cmap = get_cmap('tab10')

ax_1.bar(df['year'], df['open'], label = 'open', color = cmap(0))
ax_2.plot(df['year'], df['closed'], label = 'closed', color = cmap(0.1),linewidth = '4.5')

# 添加轴标题
ax_1.set_ylabel('open')
ax_2.set_ylabel('closed')

handles_1, labels_1 = ax_1.get_legend_handles_labels()
handles_2, labels_2 = ax_2.get_legend_handles_labels()

ax_1.set_ylim(0, 160)
ax_2.set_ylim(0, 45)
ax_1.legend(handles = handles_1 + handles_2, labels = labels_1 + labels_2, loc = 'upper left', shadow = True)
ax_1.grid(axis = 'y')
ax_1.set_title('Sales comparison')

# 修复X轴刻度问题，可选添加旋转避免重叠
ax_1.set_xticks(df['year'])
plt.xticks(rotation=45)

plt.show()

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