import matplotlib.pyplot as plt
from matplotlib.cm import ScalarMappable
data_x = [0,1,2,3]
data_hight = [60,60,80,100]
data_color = [200.,600.,0.,750.]
data_color_normalized = [x / max(data_color) for x in data_color]
fig, ax = plt.subplots(figsize=(15, 4))
my_cmap = plt.cm.get_cmap('GnBu')
colors = my_cmap(data_color_normalized)
rects = ax.bar(data_x, data_hight, color=colors)
sm = ScalarMappable(cmap=my_cmap, norm=plt.Normalize(0,max(data_color)))
sm.set_array([])
cbar = plt.colorbar(sm)
cbar.set_label('Color', rotation=270,labelpad=25)
plt.xticks(data_x)
plt.ylabel("Y")
plt.title('How to plot a bar chart with a colorbar with matplotlib ?')
plt.savefig("bar_chart_with_colorbar_01.png", bbox_inches='tight')
plt.show()