使用Python实现嵌套绘图并为条形图添加自定义标注

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导入库

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

准备数据

# 创建数据框
df = pd.DataFrame({
    "班级": ["A", "B", "C"],
    "数学": [80, 90, 70],
    "英语": [85, 80, 95],
    "科学": [90, 75, 85]
})

嵌套绘图

要创建嵌套绘图，首先需要创建一个主图，然后将子图添加到主图中。

# 创建主图
fig, ax = plt.subplots()

# 添加子图
ax_math = ax.bar(df["班级"], df["数学"], color="blue")
ax_english = ax.bar(df["班级"], df["英语"], color="red", bottom=df["数学"])
ax_science = ax.bar(df["班级"], df["科学"], color="green", bottom=df["数学"]+df["英语"])

自定义标注

为了添加自定义标注，可以使用 matplotlib.text 函数。

# 为每个条形图添加文本标注
for bar in ax_math:
    height = bar.get_height()
    ax.text(bar.get_x() + bar.get_width()/2, height, f"{int(height)}", ha="center", va="bottom")

for bar in ax_english:
    height = bar.get_height()
    ax.text(bar.get_x() + bar.get_width()/2, height, f"{int(height)}", ha="center", va="bottom")

for bar in ax_science:
    height = bar.get_height()
    ax.text(bar.get_x() + bar.get_width()/2, height, f"{int(height)}", ha="center", va="bottom")

图例

# 添加图例
plt.legend((ax_math[0], ax_english[0], ax_science[0]), ("数学", "英语", "科学"))

显示图表

plt.show()

完整代码：

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

df = pd.DataFrame({
    "班级": ["A", "B", "C"],
    "数学": [80, 90, 70],
    "英语": [85, 80, 95],
    "科学": [90, 75, 85]
})

fig, ax = plt.subplots()

ax_math = ax.bar(df["班级"], df["数学"], color="blue")
ax_english = ax.bar(df["班级"], df["英语"], color="red", bottom=df["数学"])
ax_science = ax.bar(df["班级"], df["科学"], color="green", bottom=df["数学"]+df["英语"])

for bar in ax_math:
    height = bar.get_height()
    ax.text(bar.get_x() + bar.get_width()/2, height, f"{int(height)}", ha="center", va="bottom")

for bar in ax_english:
    height = bar.get_height()
    ax.text(bar.get_x() + bar.get_width()/2, height, f"{int(height)}", ha="center", va="bottom")

for bar in ax_science:
    height = bar.get_height()
    ax.text(bar.get_x() + bar.get_width()/2, height, f"{int(height)}", ha="center", va="bottom")

plt.legend((ax_math[0], ax_english[0], ax_science[0]), ("数学", "英语", "科学"))

plt.show()

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