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

If you are okay to add pandas as a dependency you can use this implementation

>>> import pandas as pd
>>> df = pd.DataFrame(pair_array)
>>> pd.crosstab(df[0], df[1])
1    69   183  254  267  382
0
18     1    0    0    0    0
31     0    1    0    1    1
183    0    0    0    1    1
205    0    0    1    0    2
254    0    0    0    0    1