根据 for 循环中的迭代次数向列表添加不同的值

Posted 2023-02-23

【中文标题】根据 for 循环中的迭代次数向列表添加不同的值

【英文标题】：Adding a different value to a list based on number of iteration in a for loop

【发布时间】：2022-01-19 20:25:25

【问题描述】：

我是 Python 和一般编程新手，但在网站解析项目方面遇到了问题。

这是我设法编写的代码：

import requests
from bs4 import BeautifulSoup
import pandas as pd
pd.set_option('display.max_rows', None)
pd.set_option('display.max_columns', None)
pd.set_option('display.width', None)
pd.set_option('display.max_colwidth', -1)
import json

#necessary lists
url_list = [
    "https://warframe.market/items/melee_riven_mod_(veiled)",
    "https://warframe.market/items/zaw_riven_mod_(veiled)"
    ]
item_list = []
items_name = []
combined_data = []
iteration = 0


#looping for every url found in url_list
for url in url_list:
    #requesting data
    r = requests.get(url)
    soup = BeautifulSoup(r.content, "html.parser")

    #splitting the last part of the url which has the name of the item that I want to insert in the dataframe
    name = url.split("/")[4]
    items_name.append(name)

    #Finding in the parsed HTML code where the JSON file starts ( it start from <script> n°2)
    results = soup.find_all('script')[2].text.strip()
    data = json.loads(results)
    combined_data.append(data) #combining all the data into one list


    #filtering only the users who sell the items and are either "ingame" or "online"
    for payload in combined_data[iteration]["payload"]["orders"]:
        if payload["order_type"] == "sell" and (payload["user"]["status"] == "online" or payload["user"]["status"] == "ingame"):
            p = payload
            item_list.append(p) 
            #adding the items names to the item list       ???? PROBLEM ?????
            item_list = [dict(item, **'name':items_name[iteration]) for item in item_list]
    #trying to change the list from where the data gets taken from and the items name        ????? PROBLEM ????
    iteration += 1        
    
    #creating a dataframe with all the values
    df = pd.DataFrame(item_list).sort_values(by=["platinum"])

我正在尝试做但找不到解决方案，就是将 url 所指的项目的名称添加到 item_list。

例如

index	platinum	quantity	...	items name (problematic column)
1	10	1	...	melee_riven_mod_(veiled)
2	11	1	...	melee_riven_mod_(veiled)
3	12	2	...	zaw_riven_mod_(veiled)
4	...	...	...	zaw_riven_mod_(veiled)

但项目名称列对于所有行具有相同的名称，如下所示：

index	platinum	quantity	...	items name (problematic column)
1	10	1	...	melee_riven_mod_(veiled)
2	11	1	...	melee_riven_mod_(veiled)
3	12	2	...	melee_riven_mod_(veiled)
4	...	...	...	melee_riven_mod_(veiled)

所以我想问一下我在 for 循环中做错了什么？它迭代 2 次，这是 url_list 中的 url 数量，但它不会更改项目的名称。 我没看到什么？

【问题讨论】：

当我复制你的代码时，它会引发一个错误。直接复制运行的时候有没有？

我无法运行您的代码。如果你修好了，我可以帮你。

抱歉，我遇到了缩进问题。现在应该修复了

【参考方案1】：

改变

if payload["order_type"] == "sell" and (payload["user"]["status"] == "online" or payload["user"]["status"] == "ingame"):
     p = payload
     item_list.append(p)
     #adding the items names to the item list       ???? PROBLEM ?????
     item_list = [dict(item, **'name':items_name[iteration]) for item in item_list]

到这里：

if payload["order_type"] == "sell" and (payload["user"]["status"] == "online" or payload["user"]["status"] == "ingame"):
    payload['name'] = items_name[iteration]
    item_list.append(payload)

请注意，您可以使用 enumerate 循环遍历 url_list，而不是使用单独的变量 iteration 并在每次迭代时提供项目 和 其索引：

for iteration, url in enumerate(url_list):
    ....