def sort_by_value_get_col(mat):
    """
    Sort a sparse coo_matrix by values and returns the columns (the matrix has 1 row)
    :param mat: the matrix
    :return: a sorted list of tuples columns by descending values
    """
    sorted_tuples = sorted(mat, key=lambda x: x[2], reverse=True)

    if len(sorted_tuples) == 0:
        return []

    rows, columns, values = zip(*sorted_tuples)
    return columns