年阶梯气价计算方式

draft.py

# encoding=utf8
from decimal import Decimal


def create_ladders(price_name, last_reading, current_reading, price):
    """ 目前不考虑优惠，但是可以合计金额里面体现出来
        ladder['price_name'] = price_name
        ladder['last_reading'] = last_reading
        ladder['current_reading'] = current_reading
        ladder['gas'] = current_reading - last_reading
        ladder['price'] = price
        ladder['amount'] = Decimal(current_reading - last_reading) * price
    """
    ladders = []

    # 得到起数，止数和单价列表
    if price.count('|'):
        code_array = filter(lambda x: x, price.split('|'))
        price_array = zip(code_array[::2], code_array[1::2])

        price_array = [list(i) for i in price_array]
        for item in price_array:
            item[1] = int(item[1])

        assert len(price_array) > 0
        ok = False
        for i, (price, gas) in enumerate(price_array):
            if current_reading > gas > last_reading:
                if i == 0 or price_array[i - 1][1] < last_reading:
                    ladders.append([price_name, last_reading, gas, gas - last_reading, price,
                                    Decimal(gas - last_reading) * Decimal(price)])
                else:
                    ladders.append(
                        [price_name, price_array[i - 1][1], gas, gas - price_array[i - 1][1],
                         price,
                         Decimal(gas - price_array[i - 1][1]) * Decimal(price)])
            elif current_reading <= gas:
                if i == 0:
                    ladders.append(
                        [price_name, last_reading, current_reading,
                         current_reading - last_reading, price,
                         Decimal(current_reading - last_reading) * Decimal(price)])
                else:
                    # 未测试
                    if price_array[i - 1][1] > last_reading:
                        ladders.append(
                            [price_name, price_array[i - 1][1], current_reading,
                             current_reading - price_array[i - 1][1], price,
                             Decimal(current_reading - price_array[i - 1][1]) * Decimal(price)])
                    else:
                        ladders.append(
                            [price_name, last_reading, current_reading,
                             current_reading - last_reading, price,
                             Decimal(current_reading - last_reading) * Decimal(price)])
                ok = True
                break
        # ok 处理
        if not ok:
            if price_array[-1][1] > last_reading:
                ladders.append(
                    [price_name, price_array[- 1][1], current_reading,
                     current_reading - price_array[- 1][1], code_array[-1],
                     Decimal(current_reading - price_array[- 1][1]) * Decimal(code_array[-1])])
            else:
                ladders.append(
                    [price_name, last_reading, current_reading,
                     current_reading - last_reading, code_array[-1],
                     Decimal(current_reading - last_reading) * Decimal(code_array[-1])])

    else:
        ladders.append(
            [price_name, last_reading, current_reading, current_reading - last_reading, price,
             Decimal(current_reading - last_reading) * Decimal(price)])
    return ladders


if __name__ == '__main__':
    assert create_ladders('a', 100, 200, '2.5') == [['a', 100, 200, 100, '2.5', 250]]

    # 2个阶梯
    assert create_ladders('a', 29, 59, '2.5|60|3.5') == [['a', 29, 59, 30, '2.5', 75]]
    assert create_ladders('a', 30, 60, '2.5|60|3.5') == [['a', 30, 60, 30, '2.5', 75]]

    # ok
    assert create_ladders('a', 60, 70, '2.5|60|3.5') == [['a', 60, 70, 10, '3.5', 35]]
    # ok
    assert create_ladders('a', 61, 71, '2.5|60|3.5') == [['a', 61, 71, 10, '3.5', 35]]
    # ok
    assert create_ladders('a', 59, 61, '2.5|60|3.5') == [
        ['a', 59, 60, 1, '2.5', Decimal('2.5')],
        ['a', 60, 61, 1, '3.5', Decimal('3.5')],
    ]
    assert create_ladders('a', 58, 62, '2.5|60|3.5') == [
        ['a', 58, 60, 2, '2.5', 5],
        ['a', 60, 62, 2, '3.5', 7],
    ]

    ## 3个阶梯,原样复制上面的代码，然后追加阶梯，之后仍然有一组测试不通过
    assert create_ladders('a', 29, 59, '2.5|60|3.5|80|4.5') == [['a', 29, 59, 30, '2.5', 75]]
    assert create_ladders('a', 30, 60, '2.5|60|3.5|80|4.5') == [['a', 30, 60, 30, '2.5', 75]]

    # 调整后改组失败,ok
    assert create_ladders('a', 60, 70, '2.5|60|3.5|80|4.5') == [['a', 60, 70, 10, '3.5', 35]]
    # ok，这是一组临界值
    assert create_ladders('a', 61, 71, '2.5|60|3.5|80|4.5') == [['a', 61, 71, 10, '3.5', 35]]

    assert create_ladders('a', 59, 61, '2.5|60|3.5|80|4.5') == [
        ['a', 59, 60, 1, '2.5', Decimal('2.5')],
        ['a', 60, 61, 1, '3.5', Decimal('3.5')],
    ]
    assert create_ladders('a', 58, 62, '2.5|60|3.5|80|4.5') == [
        ['a', 58, 60, 2, '2.5', 5],
        ['a', 60, 62, 2, '3.5', 7],
    ]

    # 类似的补充,未发现问题
    assert create_ladders('a', 80, 90, '2.5|60|3.5|80|4.5') == [['a', 80, 90, 10, '4.5', 45]]
    assert create_ladders('a', 81, 91, '2.5|60|3.5|80|4.5') == [['a', 81, 91, 10, '4.5', 45]]

    assert create_ladders('a', 79, 81, '2.5|60|3.5|80|4.5') == [
        ['a', 79, 80, 1, '3.5', Decimal('3.5')],
        ['a', 80, 81, 1, '4.5', Decimal('4.5')],
    ]
    assert create_ladders('a', 78, 82, '2.5|60|3.5|80|4.5') == [
        ['a', 78, 80, 2, '3.5', Decimal('7')],
        ['a', 80, 82, 2, '4.5', Decimal('9')],
    ]

    # 跨两个阶梯,未发现问题
    assert create_ladders('a', 59, 81, '2.5|60|3.5|80|4.5') == [
        ['a', 59, 60, 1, '2.5', Decimal('2.5')],
        ['a', 60, 80, 20, '3.5', Decimal('70')],
        ['a', 80, 81, 1, '4.5', Decimal('4.5')],
    ]
    assert create_ladders('a', 58, 82, '2.5|60|3.5|80|4.5') == [
        ['a', 58, 60, 2, '2.5', Decimal('5')],
        ['a', 60, 80, 20, '3.5', Decimal('70')],
        ['a', 80, 82, 2, '4.5', Decimal('9')],
    ]

    # assert create_ladders('a', 1625, 1675, '1.90|390|2.28|630|2.85') == [
    #     ['a', 1625, 1675, 2, '2.5', Decimal('5')],
    # ]

    # ooo
    assert create_ladders('a', 0, 8, '1.90|390|2.28|630|2.85') == [
        ['a', 0, 8, 8, '1.90', Decimal('1.90') * Decimal('8')],
    ]

    print create_ladders('a', 1231, 1271, '1.90|390|2.28|630|2.85')