matplotlib / seaborn：将第一行和最后一行切成热图图的一半

Question

When plotting heatmaps with seaborn (and correlation matrices with matplotlib) the first and the last row is cut in halve. This happens also when I run this minimal code example which I found online.

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

data = pd.read_csv('https://raw.githubusercontent.com/resbaz/r-novice-gapminder-files/master/data/gapminder-FiveYearData.csv')
plt.figure(figsize=(10,5))
sns.heatmap(data.corr())
plt.show()

The labels at the y axis are on the correct spot, but the rows aren't completely there.

A few days ago, it work as intended. Since then, I installed texlive-xetex so I removed it again but it didn't solve my problem.

Any ideas what I could be missing?

Answer 1

不幸的是，matplotlib 3.1.1 打破了海洋热图；以及通常带有固定刻度的倒转轴。
在当前的开发版本中已修复此问题。你可能因此

• 恢复到matplotlib 3.1.0
• 使用matplotlib 3.1.2或更高版本
• 手动设置热图限制（ax.set_ylim(...)）

Answer 2

它是3.1.0和3.1.1之间的matplotlib回归中的错误，您可以通过以下方法更正此错误：

import seaborn as sns
df_corr = someDataFrame.corr()
ax = sns.heatmap(df_corr, annot=True) #notation: "annot" not "annote"
bottom, top = ax.get_ylim()
ax.set_ylim(bottom + 0.5, top - 0.5)

Answer 3

使用以上方法修复并手动设置了热图限制。

第一

ax = sns.heatmap(...

检查当前轴

ax.get_ylim()
(5.5, 0.5)

固定于

ax.set_ylim(6.0, 0)

Answer 4

我通过在我的代码中添加这一行来解决它，使用matplotlib==3.1.1：

ax.set_ylim(sorted(ax.get_xlim(), reverse=True))

注意。这样做的唯一原因是 x 轴没有改变，所以在未来的 mpl 版本中使用风险自负