How can I convert a two column array to a matrix with counts of occurences?

Question

I have the following numpy array:

import numpy as np

pair_array = np.array([(205, 254), (205, 382), (254, 382), (18, 69), (205, 382), 
                       (31         


        

Answer 1

This is crosstab:

pd.crosstab(pair_array[:,0], pair_array[:,1])

Output:

col_0  69   82   183  254  267  382
row_0                              
18       1    0    0    0    0    0
31       0    1    1    0    1    0
183      0    0    0    0    1    1
205      0    0    0    1    0    2
254      0    0    0    0    0    1