How to retrieve frequencies of the number of unique occurrences of pair letters for every possible pair of columns from a numpy matrix in python

How to retrieve frequencies of the number of unique occurrences of pair
letters for every possible pair of columns from a numpy matrix in python

References

Reference NO 1

http://stackoverflow.com/questions/15187355/how-to-retrieve-frequencies-of-the-number-of-unique-occurrences-of-pair-letters

Reference NO 2

http://stackoverflow.com/questions/17093043/want-to-count-the-number-of-values-in-a-column-that-meet-a-condition

Reference NO 3

http://stackoverflow.com/questions/16511018/python-generating-all-pairwise-unique-pairings

Reference NO 4

http://stackoverflow.com/questions/14472362/numpy-with-combinatoric-generators-how-does-one-speed-up-combinations

Reference NO 5

http://cyrille.rossant.net/playing-with-ruzzle-in-python/

Reference NO 6

http://scikit-learn.org/stable/modules/feature_extraction.html

Reference NO 7

http://www-h.eng.cam.ac.uk/help/languages/python/tutorial/

Reference NO 8

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