make colormap matplotlib 3 colors code example

Example: show matplotlib colormaps

import matplotlib as mpl
import matplotlib.pyplot as plt

def plot_colorMaps(cmap):

    fig, ax = plt.subplots(figsize=(4,0.4))
    col_map = plt.get_cmap(cmap)
    mpl.colorbar.ColorbarBase(ax, cmap=col_map, orientation = 'horizontal')

    plt.show()

for cmap_id in plt.colormaps():
    print(cmap_id)
    plot_colorMaps(cmap_id)