python3小demo

　　总结常用的功能小实例,快速学习并掌握python技能

1.墨迹天气

import requests
from lxml.html import etree
import json
import time        # 导入模块
class MoJiWeather():
    def city_name(self):  # 定义一个输入城市名称的函数
        cityname = str(input("输入城市名称："))
        return cityname
    def search_city(city_name):# 搜索这个城市
        index_url = "http://tianqi.moji.com/api/citysearch/%s"%city_name   #  构造查询相应城市天气的url
        response = requests.get(index_url)
        response.encoding = "utf-8"
        try:# 异常捕获
            city_id = json.loads(response.text).get('city_list')[0].get('cityId')# 通过上面的url获取城市的id
            city_url = "http://tianqi.moji.com/api/redirect/%s"%str(city_id)  # 通过城市id获取城市天气
            return city_url
        except:
            print('城市名输入错误')
            exit()
    def parse(city_url):# 解析函数
        response = requests.get(city_url)
        response.encoding = 'utf-8'
        html = etree.HTML(response.text)
        current_city = html.xpath("//div[@class='search_default']/em/text()")[0]#    下面都是利用xpath解析的
        print('当前城市：'+current_city)
        current_kongqi = html.xpath("//div[@class='left']/div[@class='wea_alert clearfix']/ul/li/a/em/text()")[0]
        print('空气质量：'+current_kongqi)
        current_wendu = html.xpath("//div[@class='left']/div[@class='wea_weather clearfix']/em/text()")[0]
        print('当前温度：'+current_wendu+'℃')
        current_weather = html.xpath("//div[@class='wea_weather clearfix']/b/text()")[0]
        print('天气状况：' + current_weather)
        current_shidu = html.xpath("//div[@class='left']/div[@class='wea_about clearfix']/span/text()")[0]
        print('当前湿度：'+current_shidu)
        current_fengji = html.xpath("//div[@class='left']/div[@class='wea_about clearfix']/em/text()")[0]
        print('当前风速：'+current_fengji)
        jingdian = html.xpath("//div[@class='right']/div[@class='near'][2]/div[@class='item clearfix']/ul/li/a/text()")
        print('附近景点：')
        for j in jingdian:
            print('\t\t'+j)
if __name__ == '__main__':
    print("欢迎使用墨迹天气查询系统")
    city_name = MoJiWeather.city_name(1)
    city_url = MoJiWeather.search_city(city_name)
    MoJiWeather.parse(city_url)
    print("谢谢使用本查询系统")
    input("按任意键退出...")

2.Tiobe排行榜

import json
from lxml import etree
from lxml.etree import ParseError
import requests
from requests.exceptions import RequestException

'''
    lxml实例应用
'''

'''
    获取页面数据
'''
def one_to_page(url):
    headers = {
        'user-agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/67.0.3396.62 Safari/537.36'
    }

    try:
        res = requests.get(url,headers=headers)
        body = res.text #获取网页内容
    except RequestException as e:
        print('request is error',e)

    try:
        html = etree.HTML(body,etree.HTMLParser())
        # tr 下的所有子孙节点(只获取文本数,图片资源不获取)
        result = html.xpath('//table[contains(@class,"table-top20")]/tbody/tr//text()')

        pos = 0
        for i in range(20):
            if i == 0:
                yield result[i:5]
            else:
                yield result[pos:pos+5]
            pos += 5

    except ParseError as e:
        print(e.position)


'''
    写入文件
'''
def write_file(data):
    for item in data:
        sul = {
            '2018年6月排行': item[0],
            '2017年6排行': item[1],
            '开发语言': item[2],
            '评级': item[3],
            '变化率': item[4]
        }
        # with 更好处理异常情况,进行文件的关闭后续工作
        with open('test.txt','a',encoding='utf-8') as f:
            f.write(json.dumps(sul,ensure_ascii=False)+'\n')
            f.close()
        print(sul)
    return None

'''
    主程序
'''
def main():
    url = 'https://www.tiobe.com/tiobe-index/'
    data = one_to_page(url)
    ret = write_file(data)
    if ret == None:
        print('ok')

if __name__ == '__main__':
    main()

3.新闻列表

'''
    墨迹天气文章爬虫
'''
import requests
import json
from lxml.html import etree
from lxml.etree import ParseError

'''
    解析页面内容
'''
def parseHtml(content):
    try:
        html = etree.HTML(content,etree.HTMLParser())
        # one = html.xpath('//ul[@class="advisory_list_item"]//text()')
        one = html.xpath('//ul[@class="advisory_list_item"]//li/a/@href')
        print(one)
        exit(0)
        LOOP = 8
        pos = 0
        for i in range(20):
            if i == 0:
                yield one[0:LOOP]
            else:
                yield one[pos:pos+LOOP]
            pos += LOOP

    except ParseError as e:
        print(e.position)

'''
    写入文件
'''
def write_log(data):
    for item in data:
        msg = {
            '发文时间':item[3],
            '文章标题':item[5]
        }
        with open('moji.log','a',encoding='utf-8') as f:
            f.write(json.dumps(msg,ensure_ascii=False)+'\n')
            f.close()
        print(msg)
    return None
'''
    主程序
'''
def main():

    for page in range(1,73):
        url = 'https://tianqi.moji.com/news/list/moji/{}'.format(page)
        res = requests.get(url)
        res.encoding = 'utf-8'
        content = parseHtml(res.text)
        ret = write_log(content)
        if ret is None:
            print('ok')

if __name__ == '__main__':
    main()