A bubble plot is a scatterplot with a third dimension: the **size** of the markers. It is even possible to add a fourth dimension using **colors**. It can be done using the `cmap`

argument of the `scatter()`

function of matplotlib.

```
# libraries
import matplotlib.pyplot as plt
import numpy as np
import seaborn as sns
# create data
x = np.random.rand(15)
y = x+np.random.rand(15)
z = x+np.random.rand(15)
z=z*z
# Change color with c and transparency with alpha.
# I map the color to the X axis value.
plt.scatter(x, y, s=z*2000, c=x, cmap="Blues", alpha=0.4, edgecolors="grey", linewidth=2)
# Add titles (main and on axis)
plt.xlabel("the X axis")
plt.ylabel("the Y axis")
plt.title("A colored bubble plot")
# Show the graph
plt.show()
```