python - Python CSV Writer 仅写入处理的最后一个抓取的项目
问题描述
所以我的刮刀只将最后两个项目从它处理的最后一页发送到 csv。我不知道我在哪里做错了它打印输出非常好。可能是经验丰富的眼睛能够提供帮助。
下面的代码:
from requests_html import HTMLSession
import csv
import time
def get_links(url):
_request = _session.get(url)
items = _request.html.find('li.product-grid-view.product.sale')
links = []
for item in items:
links.append(item.find('a', first=True).attrs['href'])
# print(len(links))
return links
def get_product(link):
_request = _session.get(link)
title = _request.html.find('h2', first=True).full_text
price = _request.html.find('span.woocommerce-Price-amount.amount bdi')[1].full_text
sku = _request.html.find('span.sku', first=True).full_text
categories = _request.html.find('span.posted_in', first=True).full_text.replace('Categories:', "").strip()
brand = _request.html.find('span.posted_in')[1].full_text.replace('Brand:', "").strip()
#print(brand)
product = {
'Title': title,
'Price': price,
'SKU': sku,
'Categories': categories,
'Brand': brand
}
#print(product)
return product
if __name__ == '__main__':
for page in range(1, 4):
url = 'https://www.thebassplace.com/product-category/basses/4-string/'
if page == 1:
parse_url = url
else:
parse_url = f'https://www.thebassplace.com/product-category/basses/4-string/page/{page}/'
_session = HTMLSession()
links = get_links(parse_url)
results = []
for link in links:
results.append(get_product(link))
time.sleep(1)
#print(len(results))
with open('on_sale_bass.csv', 'w', newline='', encoding='utf-8') as csv_file:
writer = csv.DictWriter(csv_file, fieldnames=results[0].keys())
writer.writeheader()
for row in results:
writer.writerow(row)
当我尝试附加记录时,记录是用 csv 编写的,但每次页面迭代都会重复标题。
解决方案
问题出在语句中results = []
,在范围循环内。results
您在循环的每次迭代中都清空了range(1, 4)
。因此,你得到的只是上一次迭代带来的东西。
请注意,我做了_session
as global
,但在这种情况下,我认为(请随时更正)在函数之间传递它是合理的。现在,试试这个。
from requests_html import HTMLSession
import csv
import time
def get_links(url):
global _session
_request = _session.get(url)
items = _request.html.find('li.product-grid-view.product.sale')
links = []
for item in items:
links.append(item.find('a', first=True).attrs['href'])
return links
def get_product(link):
global _session
_request = _session.get(link)
title = _request.html.find('h2', first=True).full_text
price = _request.html.find('span.woocommerce-Price-amount.amount bdi')[1].full_text
sku = _request.html.find('span.sku', first=True).full_text
categories = _request.html.find('span.posted_in', first=True).full_text.replace('Categories:', "").strip()
brand = _request.html.find('span.posted_in')[1].full_text.replace('Brand:', "").strip()
product = {
'Title': title,
'Price': price,
'SKU': sku,
'Categories': categories,
'Brand': brand
}
return product
if __name__ == '__main__':
results = []
for page in range(1, 4):
url = 'https://www.thebassplace.com/product-category/basses/4-string/'
if page == 1:
parse_url = url
else:
parse_url = f'https://www.thebassplace.com/product-category/basses/4-string/page/{page}/'
_session = HTMLSession()
links = get_links(parse_url)
for link in links:
product = get_product(link)
results.append(product)
#time.sleep(1)
with open('on_sale_bass.csv', 'w', newline='', encoding='utf-8') as csv_file:
writer = csv.DictWriter(csv_file, fieldnames=results[0].keys())
writer.writeheader()
for row in results:
writer.writerow(row)
我得到的一个例子: