Matplotlib - specific column of legend label

Question

import matplotlib.pyplot as plt
import numpy as np

N = 10

x = np.random.rand(N)
y = np.random.rand(N)

plt.scatter(x, y, label='1')

x = np.random.rand(N)
y = np.random.rand(N)

plt.scatter(x, y, label='2')

x = np.random.rand(N)
y = np.random.rand(N)

plt.scatter(x, y, label='3')

x = np.random.rand(N)
y = np.random.rand(N)

plt.scatter(x, y, label='4')

x = np.random.rand(N)
y = np.random.rand(N)

plt.scatter(x, y, label='5')

plt.legend(ncol=2, loc='upper left')

plt.show()

I'd like to move label '3' to the second column of the legend.

So column one should have:
1
2

And column two should have:
3
4
5

How can I do this?

Answer 1

You can put on a blank label before scatter the label 3 points with label color identical to your background color:

import matplotlib.pyplot as plt
import numpy as np

N = 10

x = np.random.rand(N)
y = np.random.rand(N)

plt.scatter(x, y, label='1')

x = np.random.rand(N)
y = np.random.rand(N)

plt.scatter(x, y, label='2')

x = np.random.rand(N)
y = np.random.rand(N)

plt.scatter(x, y, label='', c='#ffffff')
plt.scatter(x, y, label='3')

x = np.random.rand(N)
y = np.random.rand(N)

plt.scatter(x, y, label='4')

x = np.random.rand(N)
y = np.random.rand(N)

plt.scatter(x, y, label='5')
plt.legend(labels=['1','2', '', '3','4','5'], ncol=2, loc='upper left')
plt.show()

Notice that if the labels parameters not specified in plt.legend then the output will be the same as yours since it skip drawing the blank label.