matrix_list_duplicates.py

"""
This finds the duplicates in the matrix (list of lists) and returns
a list of all items "visited" and a list of all "duplicate".

This has been run like:

% python matrix.py
These items have been visited at least once: [[1, 2, 3], [3, 4, 5]]
These are the duplicates: [[1, 2, 3]]
"""


matrix = [
    [1, 2, 3], [3, 4, 5], [1, 2, 3]
]


def find_duplicates(matrix):
    visited = []
    duplicates = []

    for vector in matrix:
        if vector in visited:
            duplicates.append(vector)
        else:
            visited.append(vector)

    return visited, duplicates


if __name__ == '__main__':
    visited, duplicates = find_duplicates(matrix)

    print "These items have been visited at least once: {}".format(visited)
    print "These are the duplicates: {}".format(duplicates)