如何按类别用百分比注释计数图

Question

您好，我正在尝试向我的 5 个类别和 2 个值（旧的和年轻的）添加百分比countplot。我尝试添加来自 如何在seaborn中的条形顶部添加百分比？

我的代码：

plt.figure(figsize =(7,5))
ax = sb.countplot(data = df_x_1, x = 'concern_virus', hue = 'age')
plt.xticks(size =12)
plt.xlabel('Level of Concern', size = 14)
plt.yticks(size = 12)
plt.ylabel('Number of People', size = 12)
plt.title("Older and Younger People's Concern over the Virus", size = 16)
ax.set_xticklabels(ax.get_xticklabels(), rotation=40, ha="right");

for p in ax.patches:
    percentage = '{:.1f}%'.format(100 * p.get_height()/total)
    x = p.get_x() + p.get_width()
    y = p.get_height()
    ax.annotate(percentage, (x, y),ha='center')
plt.show()

正如您所看到的，百分比没有意义。

Answer 1

问题似乎出在上面代码中未定义的变量上：total。total应该是您要调用的数字100%，例如数据框中的总行数。这样所有显示的百分比总和就是 100。

这是一些示例代码：

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

N = 250
df_x_1 = pd.DataFrame({'concern_virus': np.random.choice(['a', 'b', 'c', 'd', 'e'], N),
                       'age': np.random.choice(['younger', 'older'], N)})
plt.figure(figsize=(7, 5))
ax = sns.countplot(data=df_x_1, x='concern_virus', order=['a', 'b', 'c', 'd', 'e'],
                   hue='age', hue_order=['younger', 'older'],
                   palette=['chartreuse', 'darkviolet'])
plt.xticks(size=12)
plt.xlabel('Level of Concern', size=14)
plt.yticks(size=12)
plt.ylabel('Number of People', size=12)
plt.title("Older and Younger People's Concern over the Virus", size=16)
ax.set_xticklabels(ax.get_xticklabels(), rotation=40, ha="right")

total = len(df_x_1)
for p in ax.patches:
    percentage = f'{100 * p.get_height() / total:.1f}%\n'
    x = p.get_x() + p.get_width() / 2
    y = p.get_height()
    ax.annotate(percentage, (x, y), ha='center', va='center')
plt.tight_layout()
plt.show()

要将文本置于栏的中心，选择ha='center'宽度的一半并将其添加到 x 位置会有所帮助。在文本中添加换行符可以帮助将文本很好地放置在栏的顶部。plt.tight_layout()可以帮助将所有标签放入绘图中。

Seaborn 允许您通过 修复 x 轴的顺序order=...。图例元素的顺序和相应的颜色可以通过hue_order=...和进行设置palette=...。

PS：对于新问题，每个年龄组的总数，不是直接循环所有条形图，而是第一个循环可以访问组：

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

label_younger = 'younger'
label_older = 'older'
df_younger = pd.DataFrame({'concern_virus': np.random.choice(['a', 'b', 'c', 'd', 'e'], 230)})
df_older = pd.DataFrame({'concern_virus': np.random.choice(['a', 'b', 'c', 'd', 'e'], 120)})
df_younger['age'] = label_younger
df_older['age'] = label_older
df_x_1 = pd.concat([df_younger, df_older], ignore_index=True)

plt.figure(figsize=(7, 5))
ax = sns.countplot(data=df_x_1, x='concern_virus', order=['a', 'b', 'c', 'd', 'e'],
                   hue='age', hue_order=[label_younger, label_older],
                   palette=['orangered', 'skyblue'])
plt.xticks(size=12)
plt.xlabel('Level of Concern', size=14)
plt.yticks(size=12)
plt.ylabel('Number of People', size=12)
plt.title("Older and Younger People's Concern over the Virus", size=16)
ax.set_xticklabels(ax.get_xticklabels(), rotation=40, ha="right")

for bars in ax.containers:
    if bars.get_label() == label_younger:
        group_total = len(df_younger)
    else:
        group_total = len(df_older)
    for p in bars.patches:
        # print(p.get_facecolor(), p.get_label())
        percentage = f'{100 * p.get_height() / group_total:.1f}%\n'
        x = p.get_x() + p.get_width() / 2
        y = p.get_height()
        ax.annotate(percentage, (x, y), ha='center', va='center')
plt.tight_layout()
plt.show()