test2.py

DATA = [
    {'number': 2, 'name': 'b'},
    {'number': 1, 'name': 'a'},
    {'number': 4, 'name': 'd'},
]


def make_table(lst, key_func=lambda v: v):
    table = {}
    for value in lst:
        key = key_func(value)
        table[key] = value
    return table


def main():
    """
    >>> main()
    1, a
    2, b
    3, None
    4, d
    5, None
    """
    table = make_table(DATA, lambda v: v['number'])
    for i in range(1, 6):
        value = table.get(i)
        print("{}, {}".format(i, value and value['name']))


if __name__ == '__main__':
    main()