當我嘗試在 csv 文件中寫入信息時，拋出錯誤：Traceback (most recent call last):File "sizeer.py", line 68, in <module> writer.writerow([name,color,price]) ValueError: I/O operation on closed fileimport requestsimport csvfrom bs4 import BeautifulSoupproxies = { "http":"http://195.189.60.97:3128", "http":"http://103.78.75.165:8080", "http":"http://212.87.220.2:3128", "http":"http://88.99.134.61:8080", "http":"http://103.102.139.178:8080", "http":"http://218.60.8.83:3129", "http":"http://124.121.105.193:8888", "http":"http://198.237.114.54:8080", "http":"http://36.67.106.58:8080", "http":"http://35.214.241.28:3128"}base_url = ...page = requests.get(base_url, proxies=proxies)if page.status_code != 200: exit("Page wasn't parsed")soup = BeautifulSoup(page.content, 'lxml')with open("result.csv", "w") as file: writer = csv.writer(file) writer.writerow(["Product","Color","Price"])#Get categoriescategory_wrapper = soup.find_all(class_="m-menu_subItem")categories = []for cw in category_wrapper: anchor = cw.find("a", recursive=False) categories.append(anchor['href'])#Iterrate categoriesfor category in categories: cat_page = requests.get(base_url + category, proxies=proxies) cat_soup = BeautifulSoup(cat_page.content, 'lxml') products_wrapper = cat_soup.find(class_="b-productList") cat_pagination = products_wrapper.find(class_="m-pagination").find_all("span") max_page = [int(s) for s in cat_pagination[-1].text.split() if s.isdigit()][0] #Iterrate category with pagination and get products如何在整個腳本執(zhí)行過程中保持文件打開？或者我每次添加內(nèi)容時都必須打開它？編輯事實上，該文件甚至沒有創(chuàng)建。
1 回答
青春有我
TA貢獻1784條經(jīng)驗 獲得超8個贊
with open("result.csv", "w") as file:
writer = csv.writer(file)
writer.writerow(["Product","Color","Price"])
文件在with塊的末尾關(guān)閉——這就是塊的目的。
您可以將所有內(nèi)容都放在塊內(nèi)，但這只會使現(xiàn)有問題變得更糟：代碼達到了多層縮進，很長并且變得難以理解。這就是為什么使用函數(shù)來組織代碼的原因。例如，如果您for在函數(shù)中設(shè)置了大循環(huán)：
def do_stuff_with(categories, writer):
for category in categories:
# lots of logic here
# use `writer.writerow` when needed
# Get everything else set up that doesn't need the file, first
categories = ... # do the BeautifulSoup input stuff
# then we can open the file and use the function:
with open("result.csv", "w") as file:
writer = csv.writer(file)
writer.writerow(["Product","Color","Price"])
do_stuff_with(categories, writer)
一旦你完成了這項工作，你可能就能想出進一步應用該技術(shù)的方法。例如，拉出最里面的邏輯，用于處理variations單個產(chǎn)品?；蛘吣憧梢杂幸粋€函數(shù)來處理數(shù)據(jù)的創(chuàng)建categories，然后return它。
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