How to set the xtick and ytick format manually of heatmap properly? The default format in my case is unacceptable.

[KylinGuo]

Here I would like know how to set the xtick and ytick format manually of heatmap properly (see the second image) as the default format in my case is unacceptable (see the first image).
I am afraid that I have misunderstood something. I just give my code ( know that the way I generate data looks ugly).

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

x_data = np.linspace(-2, 2, 11)
y_data = np.linspace(-2, 2, 11)
xx = []
yy = []
zz = []
for x in x_data:
    for y in y_data:
        z = np.exp(-(x**2 + y**2))
        xx.append(x)
        yy.append(y)
        zz.append(z)

data_dict = {"x_data": xx, "y_data": yy, "z_data": zz}
data_df = pd.DataFrame(data_dict)

pivot_data = data_df.pivot(index="x_data", columns="y_data", values="z_data")

ax = sns.heatmap(pivot_data)

plt.show()

This gives the first image. I am not satisfied with the axis format. However, the following way works wrong as the xlim and ylim should be [-2, 2]. Please see the second image.

ax.xaxis.set_major_formatter(ticker.FuncFormatter(lambda x, pos: f'{x:.3f}'))
ax.yaxis.set_major_formatter(ticker.FuncFormatter(lambda y, pos: f'{y:.3f}'))

[thuiop]

Something like

texts = [f'{float(text._text):.3f}' for text in ax.get_yticklabels()]
ax.set_yticklabels(texts)

will do the trick. Although the usecase of heatmap for numerical data is a bit odd.

[mwaskom]

This is floating point error, you could also round your x/data:

x_data = np.linspace(-2, 2, 11).round(1)
y_data = np.linspace(-2, 2, 11).round(1)