How can I plot just the colorbar of a heatmap?

Question

I would like to plot just the colorbar for a heatmap. Here is a MWE:

import seaborn as sns
import io
import matplotlib.pyplot as plt
import numpy as np


A = np.random.rand(100,100)

g = sns.heatmap(A)
plt.show()

How can I plot just its colorbar and not the heatmap itself?

`g.clear()` at the end ? If you don't want to show axes, add `plt.axis('off')` — HMH1013, Jun 08 '23 at 08:00

score 3 · Accepted Answer · answered Jun 08 '23 at 08:08

Try to handle it manually:

import matplotlib as mpl
import numpy as np

fig, ax = plt.subplots(figsize=(1, 4))
# vmin, vmax =  np.nanmin(A), np.nanmax(A)
cmap = mpl.colormaps['rocket']
norm = mpl.colors.Normalize(0, 1)  # or vmin, vmax
cbar = fig.colorbar(mpl.cm.ScalarMappable(norm, cmap), ax)
plt.tight_layout()
plt.show()

Output:

score 0 · Answer 2 · answered Jun 08 '23 at 07:53

0

Plotting just the colorbar is not possible to my knowledge. To see the whole spectrum of the colorbar, you could use a sample heatmap that is just a range from 0 to 100:

import seaborn as sns
import matplotlib.pyplot as plt

A = [[a] for a in range(100)] # sample heatmap

fig, ax = plt.subplots()

sns.heatmap(A, cbar=False, ax=ax)

cax = fig.add_axes([1.0, 0.0, 0.0, 1.0])  # Adjust the position and size

plt.show()

answered Jun 08 '23 at 07:53

Quantum

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...and it looks beautiful aswell ;) – Quantum Jun 08 '23 at 07:53
I would really like to just plot the colorbar as I want to put into my presentation separately. – Simd Jun 08 '23 at 07:54
1

Use snipping tool to cut just colors.. – Gedas Miksenas Jun 08 '23 at 08:06
@GedasMiksenas It would be great if it could all be done in Python – Simd Jun 08 '23 at 15:42
Use this with the above code 'ax.set_axis_off()' and 'cax.set_axis_off()'. This is closest what I can think of. – Gedas Miksenas Jun 09 '23 at 05:56

How can I plot just the colorbar of a heatmap?

2 Answers2