python - 注释一些线图观察

Question

我创建了一个脚本，它在 53 周的单个折线图数据点中显示 3 条线。图表有效，标签显示，但人满为患。有谁知道如何枚举注释/数据标签，所以只有偶数周显示数据标签？以下是我的问题：

import pandas as pd
import matplotlib.pyplot as plt

CA_plot_df = CA_Data.pivot_table('ED Arrivals', ['W'], 'Year').reset_index()
CA_plot_df = CA_plot_df[1:-1]
df_2021 = CA_plot_df[['W',2021]].dropna()[:-1]

plt.style.use('ggplot')
plt.rcParams['axes.facecolor'] = 'white'

fig = plt.figure(figsize = (15,8))
ax = fig.add_subplot(111)

plt.plot(CA_plot_df.W, CA_plot_df[2019], label = 'year 2019', color = '#407c38', linewidth = 2)

for i,j in zip(CA_plot_df.W,CA_plot_df[2019]):
    ax.annotate('%s' %round(j), xy=(i,j), xytext=(-2,5), textcoords='offset points')

plt.plot(CA_plot_df.W, CA_plot_df[2020], label = 'year 2020', color = '#b3b3b3', linewidth = 2)
plt.plot(df_2021.W, df_2021[2021], label = 'year 2021',color = '#d64550', linewidth = 2)

for i,j in zip(df_2021.W,df_2021[2021]):
    ax.annotate('%s' %round(j), xy=(i,j), xytext=(-2,5), textcoords='offset points')

标签： pythonpandasmatplotlibplot

Answer 1

• 最简单的选择可能是在添加注释时添加条件。
• 在以下情况下，仅在枚举值为偶数时添加注解。

for e, i, j in enumerate(zip(CA_plot_df.W, CA_plot_df[2019])):
    if e%2 == 0:
        ax.annotate('%s' %round(j), xy=(i,j), xytext=(-2,5), textcoords='offset points')


for e, i, j in enumerate(zip(df_2021.W, df_2021[2021])):
    if e%2 == 0:
        ax.annotate('%s' %round(j), xy=(i,j), xytext=(-2,5), textcoords='offset points')

工作示例

• 测试pandas 1.3.0和matplotlib 3.4.2

import pandas as pd
import seaborn as sns  # for data only

# sample data; top 50 rows
df = sns.load_dataset('tips').loc[:50, ['total_bill', 'tip']]

# add plots
ax = df.plot(y='total_bill', marker='.', xlabel='Records', ylabel='Amount ($)', figsize=(15, 8))
df.plot(y='tip', marker='.', ax=ax)

# adds every other annotation
for e, (i, j) in enumerate(df[['total_bill']].iterrows()):
    if e%2 == 0:
        ax.annotate(f'{j.values[0]:0.1f}', xy=(i, j), xytext=(-2, 5), textcoords='offset points')
        
# adds every annotation
for e, (i, j) in enumerate(df[['tip']].iterrows()):
    ax.annotate(f'{j.values[0]:0.1f}', xy=(i, j), xytext=(-2, 5), textcoords='offset points')