除了使用print()之外，还有什么方法可以保存for循环的结果吗？

Question

我正在尝试从my For循环和if循环中获取结果。我想要的两个结果是supply=demand时的最优价格和最优产品。

def supply(p):
    """
    This function calculates the supply of the video game as a function of price
    :param P: Ideal price of the game
    :return: The result of the calculated supply
    """
    supply = 500 + 90 * p
    return supply

def demand(p):
    """
    This function calculates the demand as a function of price
    :param P: Ideal price of the game
    :return: the result of the calculated demand
    """
    demand = 10000 - 35 * p
    return demand

for p in range(10 , 161, 1):
    demand_result = supply(p)
    supply_result = demand(p)
    print('Price is:', p , 'Demand # is:' , demand_result , 'Supply # is:' , supply_result)

    if demand_result == supply_result:
        p = optimal_price
        supply_result = optimal_product

print('The optimal price is ${:.2f}'.format(optimal_price))

预期结果是价格=76.00美元，产品= 7340

Answer 1

您可以将每个元素保存到一个列表中，然后将此列表保存到一个json文件中，以便下次需要时加载数据。

# importing the library that is necessary to deal with json files.
import json 

# opens a json file that exist in the current directory, the file is readable only. 
file = open("some_file.json", "r")

''' opens a json file that exist in the current directory, and if not, will create one, if the file already exists,
writing in it will overwrite what was already written in the file.''' 
file_1 = open("some_file_1.json", "w")

''' opens a json file that exist in the current directory, and if not, will create one, if the file already exists,
writing in it will not overwrite what was already written in the file, writing in it will append the new data.'''
file_2 = open("some_file_2.json", "a")

# writes into an already opened json file, doesn't work in mode "r" (readable), overwrites in "w" and appends in "a".
json.dump(new_data, file_1)

# returns json objects that exist in the file as dictionaries, works only on files that are opened with mode "r" (readable). 
json.load(file)

# closes the file after we finish using it.
file.close()

Answer 2

以下代码提供了所需的输出(最大限度地减少对原始代码的更改)

def supply(p):
    """
    This function calculates the supply of the video game as a function of price
    :param P: Ideal price of the game
    :return: The result of the calculated supply
    """
    supply = 500 + 90 * p
    return supply

def demand(p):
    """
    This function calculates the demand as a function of price
    :param P: Ideal price of the game
    :return: the result of the calculated demand
    """
    demand = 10000 - 35 * p
    return demand


for p in range(10 , 161, 1):
    demand_result = demand(p) # compute demand & supply
    supply_result = supply(p)

    #print('Price is:', p , 'Demand # is:' , demand_result, 'Supply # is:' , supply_result)

    if demand_result == supply_result: # demand meets supply
        optimal_price = p
        optimal_supply = supply_result
        break                         # break for loop since we're found match

print('The optimal price is ${:.2f}'.format(optimal_price))
print('The optimal supply is {:.2f}'.format(optimal_supply))

输出

The optimal price is $76.00
The optimal supply is 7340.00