Inserting points in elements of a list

Anonymous

I would like to transform a list, for example:

A = [((1, 1), (1, 1, 1, 1)),
     ((1, 1), (1, 1, 1, 1)),
     ((1, 1), (1, 1, 1, 2)),
     ((1, 1), (1, 1, 1, 3)),
     ((1, 1), (1, 1, 2, 1)),
     ((1, 1), (1, 1, 3, 1)),
     ((1, 1), (1, 2, 1, 1)),
     ((1, 1), (1, 2, 1, 2)),
     ((1, 1), (1, 2, 1, 3)),
     ((1, 1), (1, 3, 1, 1)),
     ((1, 1), (1, 3, 1, 2))]

into

A = [((1, 1, 0), (1, 1, 1, 1)),
     ((1, 1, 0), (1, 1, 1, 1)),
     ((1, 1, 0), (1, 1, 1, 2)),
     ((1, 1, 1), (1, 1, 1, 3)),
     ((1, 1, 1), (1, 1, 2, 1)),
     ((1, 1, 1), (1, 1, 3, 1)),
     ((1, 1, 2), (1, 2, 1, 1)),
     ((1, 1, 2), (1, 2, 1, 2)),
     ((1, 1, 2), (1, 2, 1, 3)),
     ((1, 1, 3), (1, 3, 1, 1)),
     ((1, 1, 3), (1, 3, 1, 2))]

Any suggestions?

Comments

Can you describe the algorithm used to convert from the old list to the new one? Is it just inserting zero at the end of the 0th tuple in your pair, and then increasing the inserted integer by 1 every three times?

John Palmieri ( 3 years ago )

Yes, it is exactly that. I would like to do that in a list that has len(A) = 108.

phcosta ( 3 years ago )

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def change_list(A): B = [] # new list n = 0 # integer to insert for i, pair in enumerate(A): B.append((pair[0] + (n,), pair[1])) # i counts the entries in A, so increment n every third time: # whenever i is congruent to 2 mod 3 if i % 3 == 2: n += 1 return B

Comments

Thank you. It is a very nice solution. Could you give me some references to learn a bit more about python/sagemath programming?

phcosta ( 3 years ago )

What have you looked at? The Sage tutorial (https://doc.sagemath.org/html/en/tuto...) is a place to start, as is the Beginner's Guide to Python (https://wiki.python.org/moin/Beginner...).

John Palmieri ( 3 years ago )

I have used that one: http://sagebook.gforge.inria.fr/

phcosta ( 3 years ago )

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Inserting points in elements of a list

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