爬虫爬NCBI

目标：有deg.csv第一列有500+基因编号。爬取ncbi寻找对应的gid号。
全面爬虫实现
python数据读写
防止IP被封锁的方法
常用免费代理
requests中文讲解
beautifulsoup——html解析工具

pip install beautifulsoup4
3.编写脚本提取编号。
已经找到方法提取基因编号和对应的GO编号了基因编号转换方法
爬虫代码仍然附上：小心使用，IP可能会被封。

#!/usr/bin/env python3
# -*- coding: utf-8 -*-

import requests,random
import csv
from bs4 import BeautifulSoup
#https://www.ncbi.nlm.nih.gov/gene/?term=Zm00001d036521
#payload={'term':'Zm00001d036521'}
#genename='Zm00001d036521'

#反反爬虫部署，添加headers,random访问，增加代理，使用代理访问。
user_agents=['Mozilla/5.0 (Windows NT 6.1; rv:2.0.1) Gecko/20100101 Firefox/4.0.1','Mozilla/5.0 (Windows; U; Windows NT 6.1; en-us) AppleWebKit/534.50 (KHTML, like Gecko) Version/5.1 Safari/534.50','Opera/9.80 (Windows NT 6.1; U; en) Presto/2.8.131 Version/11.11']    
def getGid(genename): 
    #files={'file':open('deg.csv','rb')}
    payload={'term':genename}
    headers={'User-Agent':random.choice(user_agents)}
    proxies={'http':'74.59.132.126:49073','https':'74.59.132.126:49073'}
    url="https://www.ncbi.nlm.nih.gov/gene/"
    #req=requests.get(url,headers=headers,params=payload,proxies=proxies)
    req=requests.get(url,headers=headers,params=payload)
    html=req.text  
    bf=BeautifulSoup(html,"html5lib")
    h1=bf.find_all('h1',id='gene-name') 
    a_bf=BeautifulSoup(str(h1[0]))
    a=a_bf.find_all('span')
    #此处的gid就是我们要的基因的GID值
    gid = a[0].text.replace('\xa0'*8,'\n\n')  
    return gid  

    
genecount=csv.reader(open('deg.csv','r'))

gene_table=['gid']
locus=['genename']

for geneid in genecount:
    print(geneid[0])
    gid=getGid(geneid[0])
    gene_table.append(gid)
    locus.append(geneid)
    time.sleep(random.random()) #暂停[0,1)秒

with open('out.csv','w',newline='') as f:
    writer=csv.writer(f)
    for row in gene_table:
        writer.writerow(row)