第一周学习总结

这一周我学习了python的一些基本语法和函数 以及如何从不同类型的网站爬虫

爬取了丁香园-的疫情数据还有拉勾网，猫眼的一些信息

学到两种方法，一种是xpath方法，一种是正则表达式

xpath

import requests
from lxml import etree
import xlwt
url='http://www.beijing.gov.cn/hudong/hdjl/com.web.consult.consultDetail.flow?originalId=AH20021900306'
headers = {
    "user-agent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/71.0.3578.98 Safari/537.36"
}


response=requests.post(url,headers=headers)



res_html=etree.HTML(response.text)//将爬取出的数据解析为要xpath的形式
dd_list=res_html.xpath('//*[@id="f_baner"]/div[1]/div[1]/div[2]/strong/text()')[0].strip()
print(dd_list)

提取选择的文字，.strip()将空格切割出去

 还有要爬取的数据就在源代码上，用正则表达式

import requests
import re
import xlwt

url = 'https://maoyan.com/board/4?'
headers = {
    "user-agent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/71.0.3578.98 Safari/537.36"
}


def get_page(url):
    try:
        response = requests.get(url, headers=headers)
        response.encoding = 'utf-8'
        if response.status_code == 200:
            return response.text
        else:
            print('获取网页失败')
    except Exception as e:
        print(e)


def get_info(page):
    items = re.findall('.*?class="name"><a href=".*?" title="(.*?)".*?">.*?</a></p>.*?<p class="releasetime">(.*?)</p>',page,re.S)//(.*?)表示你要爬取的内容
    for item in items:
        data = {}
        data['name'] = item[0]
        data['time'] = item[1]
        # print (123)
        print(data)
        yield data


urls = ['https://maoyan.com/board/4?offset={}'.format(i * 10) for i in range(10)]
DATA = []
for url in urls:
    print (url)
    page = get_page(url)
    datas = get_info(page)
    for data in datas:
        DATA.append(data)  # 将所有的数据添加到DATA里

f = xlwt.Workbook(encoding='utf-8')
sheet01 = f.add_sheet(u'sheet1', cell_overwrite_ok=True)
sheet01.write(0, 0, 'name')  # 第一行第一列
sheet01.write(0, 1, 'time')  # 第一行第一列
# 写内容
for i in range(len(DATA)):
    sheet01.write(i + 1, 0, DATA[i]['name'])
    sheet01.write(i + 1, 1, DATA[i]['time'])

    print('p', end='')
f.save('F:\作业.xls')

还有数据在json上是通过ajax来获取的

import requests
import time
import json
import xlwt
urls='https://www.lagou.com/jobs/list_%E7%88%AC%E8%99%AB/p-city_0?&cl=false&fromSearch=true&labelWords=&suginput='
url = 'https://www.lagou.com/jobs/positionAjax.json?needAddtionalResult=false'

headers = {
    'Host': 'www.lagou.com',
    'Origin': 'https://www.lagou.com',
    'Referer': 'https://www.lagou.com/jobs/list_%E7%88%AC%E8%99%AB/p-city_0?&cl=false&fromSearch=true&labelWords=&suginput=',
    'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/79.0.3945.79 Safari/537.36',
    'X-Requested-With': 'XMLHttpRequest'

}


# data参数在network/XHR中找到包含数据的网页，然后在该网页headers的最下面可以找到data参数。
# 每一页url不变，但data里面的参数会变，是用来控制搜索关键字和页数的。
def get_page(url, i):
    data = {
        'first': 'false',
        'kd': '爬虫',  # 搜索关键词  改关键字的时候，headers里面的referer也要改。
        'pn': i  # 第几页
    }
    try:
        s = requests.Session()
        s.get(urls, headers=headers, timeout=3)  # 请求首页获取cookies
        cookie = s.cookies  # 为此次获取的cookies
        response = s.post(url, data=data, headers=headers, cookies=cookie, timeout=3)  # 获取此次文本
        time.sleep(5)

        response.raise_for_status()
        response.encoding = response.apparent_encoding

        return response.json()
    except requests.ConnectionError as e:
        print('Error:', e.args)


def get_info(json):
    json = json['content']['positionResult']['result']

    for item in json:
        data = {}
        data['companyFullName'] = item['companyFullName']
        data['city'] = item['city']
        data['district'] = item['district']
        data['education'] = item['education']
        data['financeStage'] = item['financeStage']
        data['industryField'] = item['industryField']
        data['companySize'] = item['companySize']
        data['positionName'] = item['positionName']
        data['salary'] = item['salary']
        data['workYear'] = item['workYear']

        yield data


DATA = []
for i in range(1, 3):
    json = get_page(url, i)

    print('请求：' + str(i) + url)
    time.sleep(2)
    datas = get_info(json)  # 如果这一步出了问题，那么可能就是因为上一步就出了问题。
    for data in datas:
        DATA.append(data)
'''
with open('./拉勾网.text','w',encoding='utf-8') as fp:
    fp.write(str(DATA))'''

'''f = xlwt.Workbook(encoding='utf-8')
sheet01 = f.add_sheet(u'sheet1', cell_overwrite_ok=True)
sheet01.write(0, 0, 'companyFullName')  # 第一行第一列
sheet01.write(0, 1, 'city')
sheet01.write(0, 2, 'district')
sheet01.write(0, 3, 'education')
sheet01.write(0, 4, 'financeStage')
sheet01.write(0, 5, 'positionName')
sheet01.write(0, 6, 'salary')
sheet01.write(0, 7, 'workYear')
sheet01.write(0, 8, 'companySize')
sheet01.write(0, 9, 'industryField')

# 写内容
for i in range(len(DATA)):
    sheet01.write(i + 1, 0, DATA[i]['companyFullName'])
    sheet01.write(i + 1, 1, DATA[i]['city'])
    sheet01.write(i + 1, 2, DATA[i]['district'])
    sheet01.write(i + 1, 3, DATA[i]['education'])
    sheet01.write(i + 1, 4, DATA[i]['financeStage'])
    sheet01.write(i + 1, 5, DATA[i]['positionName'])
    sheet01.write(i + 1, 6, DATA[i]['salary'])
    sheet01.write(i + 1, 7, DATA[i]['workYear'])
    sheet01.write(i + 1, 8, DATA[i]['companySize'])
    sheet01.write(i + 1, 9, DATA[i]['industryField'])
    print('p', end='')
f.save(u'F:\爬虫.xls')
'''