Python color clases in a scatter plot

Question

i want to scatter plot 2 variables and color the points according to a 3rd variable which is a qualitative variable contains 2 classes.

df.plot(kind='scatter', x='TotalIncome', y='LoanAmount', figsize=(10, 6))
plt.xlabel('total income')
plt.ylabel('loan amount')
plt.show()

Answer 1

It is straightforward to colour individual points with respect to a third variable. You just need to map this qualitative variable to something that can represent a colour. For example, if this third variable were 'c' in the following code:

import matplotlib.pyplot as plt

def map_col(col):

    if col == 'y_odd':
        mapped_col = 0
    elif col == 'y_even':
        mapped_col = 1

    return mapped_col


x = [1, 4, 2, 7, 4, 9]
y = [4, 1, 3, 6, 8, 2]
c = ['y_even', 'y_odd', 'y_odd', 'y_even', 'y_even', 'y_even']

color = [map_col(col) for col in c]

plt.scatter(x, y, s=100, c=color, cmap="gnuplot")

plt.show()

For a list of available color maps see:

https://matplotlib.org/3.1.0/tutorials/colors/colormaps.html