Missing labels in matplotlib scatter plot legend

Question

Can't seem to figure out why my legend is missing the other two target names.

%matplotlib inline
import matplotlib.pyplot as plt
from sklearn import datasets


iris=datasets.load_iris()
plt.figure(figsize=(8,8))
plt.scatter(iris.data[:, 0], iris.data[:, 2], c=iris.target)
plt.xlabel(iris.feature_names[0])
plt.ylabel(iris.feature_names[2])
plt.title('Iris Dataset')
plt.legend(iris.target_names, loc='lower right')

Answer 1

This might not be the best solution, but you will have to loop through the different target types and call scatter with a specific color and label argument:

import matplotlib.pyplot as plt
from sklearn import datasets

iris=datasets.load_iris()
plt.figure(figsize=(8,8))

for target in set(iris.target):
    print target
    x = [iris.data[i,0] for i in range(len(iris.target)) if iris.target[i]==target]
    y = [iris.data[i,2] for i in range(len(iris.target)) if iris.target[i]==target]
    plt.scatter(x, y, color=['red', 'blue', 'green'][target], label=iris.target_names[target])
plt.xlabel(iris.feature_names[0])
plt.ylabel(iris.feature_names[2])
plt.title('Iris Dataset')
plt.legend(iris.target_names, loc='lower right')
plt.show()

This is the results of this code.