python出现RuntimeError错误问题及解决

下面是出现的错误解释

RuntimeError: 
        An attempt has been made to start a new process before the
        current process has finished its bootstrapping phase.
 
        This probably means that you are not using fork to start your
        child processes and you have forgotten to use the proper idiom
        in the main module:
 
            if __name__ == '__main__':
                freeze_support()
                ...
 
        The "freeze_support()" line can be omitted if the program
        is not going to be frozen to produce an executable.

下面是出现错误代码的原代码

import multiprocessing as mp
import time
from urllib.request import urlopen,urljoin
from bs4 import BeautifulSoup
import re

base_url = "https://morvanzhou.github.io/"

#crawl爬取网页
def crawl(url):
   response = urlopen(url)
   time.sleep(0.1)
   return response.read().decode()

#parse解析网页
def parse(html):
   soup = BeautifulSoup(html,'html.parser')
   urls = soup.find_all('a',{"href":re.compile('^/.+?/$')})
   title = soup.find('h1').get_text().strip()
   page_urls = set([urljoin(base_url,url['href'])for url in urls])
   url = soup.find('meta',{'property':"og:url"})['content']
   return title,page_urls,url

unseen = set([base_url])
seen = set()
restricted_crawl = True

pool = mp.Pool(4)
count, t1 = 1, time.time()
while len(unseen) != 0:                 # still get some url to visit
   if restricted_crawl and len(seen) > 20:
           break
   print('\nDistributed Crawling...')
   crawl_jobs = [pool.apply_async(crawl, args=(url,)) for url in unseen]
   htmls = [j.get() for j in crawl_jobs]      # request connection

print('\nDistributed Parsing...')
   parse_jobs = [pool.apply_async(parse, args=(html,)) for html in htmls]
   results = [j.get() for j in parse_jobs]    # parse html

print('\nAnalysing...')
   seen.update(unseen)         # seen the crawled
   unseen.clear()              # nothing unseen

for title, page_urls, url in results:
       print(count, title, url)
       count += 1
       unseen.update(page_urls - seen)     # get new url to crawl
print('Total time: ％.1f s' ％ (time.time()-t1))    # 16 s !!!

这是修改后的正确代码

import multiprocessing as mp
import time
from urllib.request import urlopen,urljoin
from bs4 import BeautifulSoup
import re
 
base_url = "https://morvanzhou.github.io/"
 
#crawl爬取网页
def crawl(url):
    response = urlopen(url)
    time.sleep(0.1)
    return response.read().decode()
 
#parse解析网页
def parse(html):
    soup = BeautifulSoup(html,'html.parser')
    urls = soup.find_all('a',{"href":re.compile('^/.+?/$')})
    title = soup.find('h1').get_text().strip()
    page_urls = set([urljoin(base_url,url['href'])for url in urls])
    url = soup.find('meta',{'property':"og:url"})['content']
    return title,page_urls,url
 
def main():
    unseen = set([base_url])
    seen = set()
    restricted_crawl = True
 
    pool = mp.Pool(4)
    count, t1 = 1, time.time()
    while len(unseen) != 0:                 # still get some url to visit
        if restricted_crawl and len(seen) > 20:
                break
        print('\nDistributed Crawling...')
        crawl_jobs = [pool.apply_async(crawl, args=(url,)) for url in unseen]
        htmls = [j.get() for j in crawl_jobs]      # request connection
 
        print('\nDistributed Parsing...')
        parse_jobs = [pool.apply_async(parse, args=(html,)) for html in htmls]
        results = [j.get() for j in parse_jobs]    # parse html
 
        print('\nAnalysing...')
        seen.update(unseen)         # seen the crawled
        unseen.clear()              # nothing unseen
 
        for title, page_urls, url in results:
            print(count, title, url)
            count += 1
            unseen.update(page_urls - seen)     # get new url to crawl
    print('Total time: ％.1f s' ％ (time.time()-t1))    # 16 s !!!
 
 
if __name__ == '__main__':
    main()

综上可知，就是把你的运行代码整合成一个函数，然后加入

if __name__ == '__main__':
    main()

这行代码即可解决这个问题。

python报错:RuntimeError

python报错：RuntimeError:fails to pass a sanity check due to a bug in the windows runtime这种类型的错误

这种错误原因

1.当前的python与numpy版本之间有什么问题，比如我自己用的python3.9与numpy1.19.4会导致这种报错。

2.numpy1.19.4与当前很多python版本都有问题。

解决办法

在File->Settings->Project:pycharmProjects->Project Interpreter下将numpy版本降下来就好了。

1.打开interpreter，如下图：

2.双击numpy修改其版本：

3.勾选才能修改版本，将需要的低版本导入即可：

弄完了之后，重新运行就好。

来源：https://blog.csdn.net/weixin_42099082/article/details/89365643