matplotlibでcolorbarの高さと図を揃える方法についてメモ。

import matplotlib
import matplotlib.axes
import matplotlib.pyplot as plt
import numpy as np
from mpl_toolkits.axes_grid1 import make_axes_locatable

f"{matplotlib.__version__=}"

"matplotlib.__version__='3.8.0'"

# 乱数発生用ジェネレータ
rng = np.random.default_rng(334)

fig, ax = plt.subplots(figsize=(3.0, 3.0), dpi=144)
ax: matplotlib.axes.Axes
mappable = ax.scatter(
    rng.random(100), rng.random(100), c=rng.random(100), vmin=0, vmax=1
)

# layout
ax.set_xlim(-0.05, 1.05)
ax.set_ylim(-0.05, 1.05)
ax.set_aspect("equal", adjustable="box")

# ** 【本題】colorbar用の領域の切り出し **
divider = make_axes_locatable(ax)
cax = divider.append_axes(position="right", size="5%", pad="3%")
# ************************************

# caxの指定
fig.colorbar(mappable, cax=cax)

fig.tight_layout()

まとめ

from mpl_toolkits.axes_grid1 import make_axes_locatable

ax: matplotlib.axes.Axes
figure: matplotlib.figure.Figure

# colorbar用の領域の切り出し
divider = make_axes_locatable(ax)
cax = divider.append_axes(position="right", size="5%", pad="3%")

# caxの指定
fig.colorbar(mappable, cax=cax)