008. Python字典排序

Bigger price

一、題目描述

要求：有一個列表，列表的內容是字典；字典的內容是貨物：價格鍵值對，給定參數n，返回最貴的n個貨物的字典列表

輸入：字典列表和n

輸出：字典列表

示例：

bigger_price(2, [
    {"name": "bread", "price": 100},
    {"name": "wine", "price": 138},
    {"name": "meat", "price": 15},
    {"name": "water", "price": 1}
]) == [
    {"name": "wine", "price": 138},
    {"name": "bread", "price": 100}
]

bigger_price(1, [
    {"name": "pen", "price": 5},
    {"name": "whiteboard", "price": 170}
]) == [{"name": "whiteboard", "price": 170}]

二、解題示例

1. lambda、排序

def bigger_price(limit: int, data: list) -> list:
    """
        TOP most expensive goods
    """
    # your code here
    sorted_list = sorted(data, key=lambda x: x['price'])[-limit:]
    sorted_list.reverse()
    return sorted_list


if __name__ == '__main__':
    from pprint import pprint
    print('Example:')
    pprint(bigger_price(2, [
        {"name": "bread", "price": 100},
        {"name": "wine", "price": 138},
        {"name": "meat", "price": 15},
        {"name": "water", "price": 1}
    ]))

    # These "asserts" using for self-checking and not for auto-testing
    assert bigger_price(2, [
        {"name": "bread", "price": 100},
        {"name": "wine", "price": 138},
        {"name": "meat", "price": 15},
        {"name": "water", "price": 1}
    ]) == [
        {"name": "wine", "price": 138},
        {"name": "bread", "price": 100}
    ], "First"

    assert bigger_price(1, [
        {"name": "pen", "price": 5},
        {"name": "whiteboard", "price": 170}
    ]) == [{"name": "whiteboard", "price": 170}], "Second"

    print('Done! Looks like it is fine. Go and check it')

2.精簡寫法

def bigger_price(limit, data):
    return sorted(data, key=lambda x: x['price'], reverse=True)[:limit]

if __name__ == '__main__':
    from pprint import pprint
    print('Example:')
    pprint(bigger_price(2, [
        {"name": "bread", "price": 100},
        {"name": "wine", "price": 138},
        {"name": "meat", "price": 15},
        {"name": "water", "price": 1}
    ]))

    # These "asserts" using for self-checking and not for auto-testing
    assert bigger_price(2, [
        {"name": "bread", "price": 100},
        {"name": "wine", "price": 138},
        {"name": "meat", "price": 15},
        {"name": "water", "price": 1}
    ]) == [
        {"name": "wine", "price": 138},
        {"name": "bread", "price": 100}
    ], "First"

    assert bigger_price(1, [
        {"name": "pen", "price": 5},
        {"name": "whiteboard", "price": 170}
    ]) == [{"name": "whiteboard", "price": 170}], "Second"

    print('Done! Looks like it is fine. Go and check it')