为什么这段代码只下载一页的数据？

Question

试过很多次了，还是不行：

import requests
from lxml import html, etree
from selenium import webdriver
import time, json

#how many page do you want to scan
page_numnotint = input("how many page do you want to scan")
page_num = int(page_numnotint)
file_name = 'jd_goods_data.json'


url = 'https://list.jd.com/list.html?cat=1713,3264,3414&page=1&delivery=1&sort=sort_totalsales15_desc&trans=1&JL=4_10_0#J_main'
driver = webdriver.Chrome()
driver.get(url)
base_html = driver.page_source
selctor = etree.HTML(base_html)
date_info = []
name_data, price_data = [], []
jd_goods_data = {}
for q in range(page_num):
    i = int(1)
    while True:
        name_string = '//*[@id="plist"]/ul/li[%d]/div/div[3]/a/em/text()' %(i)
        price_string = '//*[@id="plist"]/ul/li[%d]/div/div[2]/strong[1]/i/text()' %(i)
        if i == 60:
            break
        else:
            i += 1
        name = selctor.xpath(name_string)[0]
        name_data.append(name)
        price = selctor.xpath(price_string)[0]
        price_data.append(price)
        jd_goods_data[name] = price

        print(name_data)
        with open(file_name, 'w') as f:
            json.dump(jd_goods_data, f)
    time.sleep(2)
    driver.find_element_by_xpath('//*[@id="J_bottomPage"]/span[1]/a[10]').click()
    time.sleep(2)

    # for k, v in jd_goods_data.items():
    #     print(k,v)

我正在尝试下载一些详细信息，但它不起作用。如果输入 2 进行扫描，它只会下载一页详细信息，但会下载两次！

Answer 1

好的，您定义了 q，但实际上并没有这样使用它。在这种情况下，约定是将这个未使用的变量命名为 _。我的意思是，而不是做

for q in range(page_num):

你应该做的

for _ in range(page_num):

这样，其他程序员会直接知道你没有使用q，只想重复你的操作。

这意味着（由于某些原因）行 driver.find_element_by_xpath('//*[@id="J_bottomPage"]/span[1]/a[10]').click() 没有正确执行。肯定有办法让它发挥作用。但在你的例子中，我试探性地看到你的 url 包含一个名称为 page 的参数。我建议您改用它。因此，这导致实际使用变量 q，如下所示：

import requests
from lxml import html,etree
from selenium import webdriver
import time, json

#how many page do you want to scan
page_numnotint = input("how many page do you want to scan")
page_num = int(page_numnotint)
file_name = 'jd_goods_data.json'

driver = webdriver.Chrome()
date_info = []
name_data, price_data = [], []
jd_goods_data = {}
for q in range(page_num):
    url = 'https://list.jd.com/list.html?cat=1713,3264,3414&page={page}&delivery=1&sort=sort_totalsales15_desc&trans=1&JL=4_10_0#J_main'.format(page=q)
    driver.get(url)
    base_html = driver.page_source
    selctor = etree.HTML(base_html)
    i = 1
    while True:
        name_string = '//*[@id="plist"]/ul/li[%d]/div/div[3]/a/em/text()' %(i)
        price_string = '//*[@id="plist"]/ul/li[%d]/div/div[2]/strong[1]/i/text()' %(i)
        if i == 60:
            break
        else:
            i += 1
        name = selctor.xpath(name_string)[0]
        name_data.append(name)
        price = selctor.xpath(price_string)[0]
        price_data.append(price)
        jd_goods_data[name] = price

        print(name_data)

with open(file_name, 'w') as f:
    json.dump(jd_goods_data, f)

driver.quit()

为什么这段代码只下载一页的数据？

Why is this code only downloading one page's data?

python

python-3.x

pyspider