线程池

from concurrent.futures import ThreadPoolExecutor,ProcessPoolExecutor


def func(name):
    for i in range(1000):
        print(name, i)


if __name__ == '__main__':
    with ThreadPoolExecutor(50) as f:  # 创建一个有50个线程的线程池
        for i in range(100):  # 分配100个任务
            f.submit(func, name=f"线程{i}")
    #等待线程池中的任务全部执行完毕，才执行(守护)
    print("over!!!")

 

 

线程池爬取新发地菜价

import requests
from concurrent.futures import ThreadPoolExecutor
import csv
# 创建csv文件的表头
with open("vg_price.csv", "w", encoding="utf-8") as f:
    content = csv.writer(f)
    content.writerow(["品名", "最低价", "最高价", "平均价", "发布日期"])
def download_onepage(url,number):
    # 请求头带的参数
    params = {
        "limit": 20,
        "current": number,
        "pubDateStartTime": "",
        "pubDateEndTime": "",
        "prodPcatid": "",
        "prodCatid": "",
        "prodName":"",
    }
    resp = requests.get(url,params = params) #需要请求的url
    dic = resp.json()
    # print(dic)
    vegetables_list = dic["list"]
    #自己创建一个储存需求数据的新字典
    new_dic = {
        "prodName": "",
        "lowPrice": "",
        "highPrice": "",
        "avgPrice": "",
        "pubDate": "",
    }
    for vegetable in vegetables_list:
        # print(vegetable["prodName"],vegetable["lowPrice"],vegetable["highPrice"],vegetable["avgPrice"],vegetable["pubDate"])
        new_dic["prodName"]=vegetable["prodName"]
        new_dic["lowPrice"]=vegetable["lowPrice"]
        new_dic["highPrice"]=vegetable["highPrice"]
        new_dic["avgPrice"]=vegetable["avgPrice"]
        new_dic["pubDate"]=vegetable["pubDate"]
        # 创建csv文件，把爬取的数据写入到文件中去
        with open("vg_price.csv", "a", encoding="utf-8") as f:
            content = csv.writer(f)
            content.writerow(new_dic.values())
        # print(new_dic)
if __name__ == '__main__':
    with ThreadPoolExecutor(50) as f: #创建一个有50个线程的线程池
        url = "http://www.xinfadi.com.cn/getPriceData.html"
        for i in range(1,200):  #创建200个任务
            f.submit(download_onepage, url, i)  #提交需要操作的函数，url爬取的链接地址，i代表当前爬取的页数

    print("over!!!")