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python - Python - 如何计算和记住循环中的出现次数

问题描述

希望我能尽可能清楚地解释我正在尝试做的事情。

我每 2 秒运行一次 while 循环，以从 2 个具有不同值的不同商店获取更新的值：

字典看起来像这样：

#2 seconds
{'lastUpdateId': 202588846, 'store1': [['24.43000000', '0.00606000'], ['24.42000000', '14.76000000'], ['24.39000000', '2.65760000'], ['24.38000000', '29.59867000'], ['24.35000000', '7.71171000']], 'store2': [['24.47000000', '0.22601000'], ['24.52000000', '0.72000000'], ['24.53000000', '3.28839000'], ['24.54000000', '5.63226000'], ['24.55000000', '20.64052000']]}
#2 seconds
{'lastUpdateId': 202588904, 'store1': [['24.45000000', '0.22596000'], ['24.44000000', '12.84000000'], ['24.43000000', '22.43211000'], ['24.42000000', '5.87234000'], ['24.39000000', '2.65760000']], 'store2': [['24.51000000', '0.00003000'], ['24.52000000', '2.80979000'], ['24.53000000', '17.64938000'], ['24.67000000', '3.41000000'], ['24.68000000', '115.07610000']]}

现在我想要做的是在循环内比较商店 1 中的第二个值与商店 2 的第二个值，如果计数为 10，我想最多计数 10 次

我希望它继续到下一行代码，但这是我被卡住的地方我不知道该怎么做，我能做些什么让 python 记住循环计数？

这是我到目前为止所尝试的：

import time
def testing():

    stores = {'lastUpdateId': 202588846, 'store1': [['24.43000000', '0.00606000'], ['24.42000000', '14.76000000'], ['24.39000000', '2.65760000'], ['24.38000000', '29.59867000'], ['24.35000000', '7.71171000']], 'store2': [['24.47000000', '0.22601000'], ['24.52000000', '0.72000000'], ['24.53000000', '3.28839000'], ['24.54000000', '5.63226000'], ['24.55000000', '20.64052000']]}

    firststore = [i[1] for i in stores['store1']]

    secondstore = [e[1] for e in stores['store2']]

    offer1 = float(firststore[0]) + float(firststore[1]) + float(firststore[2])


    offer2 = float(secondstore[0]) + float(secondstore[1]) + float(secondstore[2])


    count = 0

    if offer1 > offer2:

        count+=1

        print("This store has the lesser better deal")

        if count == 10:
            print("go ahead and buy")

    if offer2 > offer1:
        count+=1
        print("this other store has the lesser letter deal")

        if count == 10:
            print("go buy this")

i = 0
while True:
    i+=1
    testing()
    time.sleep(2)

能给我一个更好的主意吗？也许有一个for循环并追加？

标签： pythonloopsfor-loop

解决方案

您正在寻找的是发电机。这是对生成器及其工作原理的一个很好的解释。

我将您的比较代码分解为一个单独的生成器函数，offer_comparer通过调用生成器函数将其分配给生成器对象compare_offer。next调用开始函数执行并在第一个返回yield。

然后，每次调用offer_comparer.send(<params>)都会将 offer1 和 offer2 发送到offers生成器函数中的变量。

这应该给你你正在寻找的东西。

import time


def compare_offers():
    count_max = 10
    while True:
        count1 = 0
        count2 = 0
        while count1 < count_max and count2 < count_max:
            offers = yield
            offer1, offer2 = offers[0], offers[1]
            if offer1 > offer2:
                count1 += 1
                print("Store1 has the better deal")
                if count1 == count_max:
                    print("go ahead and buy from store1")
            elif offer2 > offer1:
                count2 += 1
                print("Store2 has the better deal")
                if count2 == count_max:
                    print("go buy this from store2")


offer_comparer = compare_offers()
next(offer_comparer)


def testing():
    stores = {'lastUpdateId': 202588846,
              'store1': [['24.43000000', '0.00606000'],
                         ['24.42000000', '14.76000000'],
                         ['24.39000000', '2.65760000'],
                         ['24.38000000', '29.59867000'],
                         ['24.35000000', '7.71171000']],
              'store2': [['24.47000000', '0.22601000'],
                         ['24.52000000', '0.72000000'],
                         ['24.53000000', '3.28839000'],
                         ['24.54000000', '5.63226000'],
                         ['24.55000000', '20.64052000']]}

    firststore = [float(i[1]) for i in stores['store1']]
    secondstore = [float(e[1]) for e in stores['store2']]

    offer1 = sum(firststore[:3])
    offer2 = sum(secondstore[:3])

    offer_comparer.send((offer1, offer2))


i = 0
while True:
    i += 1
    testing()
    time.sleep(2)

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