以特定顺序连接散点图matplotlib

Question

I would like to use matplotlib to plot a scatter plot of a list of tuples, whose elements are x and y coordinates. Their connectivity is determined by another list that says which point is connected to which. What I have so far is this:

import itertools
import matplotlib.pyplot as plt

coords = [(0.0, 0.0), (1.0, 1.0), (1.0, 0.0), (2.0, 1.0), (2.0, 0.0), (3.0, 1.0)]
connectivity = coords[0] <--> coords[1], coords[2]
               coords[1] <--> coords[0], coords[2], coords[3]
               coords[2] <--> coords[0], coords[1], coords[4]
               coords[3] <--> coords[1], coords[3], coords[5]
               coords[4] <--> coords[2], coords[3], coords[5]
               coords[5] <--> coords[3], coords[4]
x, y = zip(*coords)
plt.plot(x, y, '-o')
plt.show()

I know the connectivity part is not actual python script. I included this to show everyone how the points are supposed to be connected. When running this script (without the connectivity bit) I get the below graph:

However, I would like to have the plot appear as:

Any ideas how I could go about do this?

Answer 1

Just plot each segment separately. This also allows for more flexibility as you can independently change the colors, add direction arrows, etc, for each connection.

Here, I used a Python dictionary to hold your connectivity info.

import matplotlib.pyplot as plt

coords = [(0.0, 0.0), (1.0, 1.0), (1.0, 0.0), (2.0, 1.0), (2.0, 0.0), (3.0, 1.0)]
connectivity = {0: (1,2),     #coords[0] <--> coords[1], coords[2]
                1: (0, 2, 3), #coords[1] <--> coords[0], coords[2], coords[3]
                2: (0, 1, 4), #coords[2] <--> coords[0], coords[1], coords[4]
                3: (1, 3, 5), #coords[3] <--> coords[1], coords[3], coords[5]
                4: (2, 3, 5), #coords[4] <--> coords[2], coords[3], coords[5]
                5: (3, 4)     #coords[5] <--> coords[3], coords[4]
                }
x, y = zip(*coords)
plt.plot(x, y, 'o')  # plot the points alone
for k, v in connectivity.iteritems():
    for i in v:  # plot each connections
        x, y = zip(coords[k], coords[i])
        plt.plot(x, y, 'r')
plt.show()

There are duplicate lines here based on how you presented the connectivity, for example, (0,1) and (1,0) . I'm assuming that you'll eventually want to put in the direction, so I left them in.