硒 - 单击按钮

问题描述

我正在尝试将 Lynda.com 提供的所有课程的名称连同主题一起提取出来，以便它以2D 绘图 -- Soane 项目:与 Paul F. Aubin 一起使用 BIM 恢复丢失的纪念碑"的形式出现在我的列表中'.所以我正在尝试编写一个脚本，该脚本将转到 http://www.lynda.com/上的每个主题站点地图/类别 并拉出课程列表.我已经设法让 Selenium 从一个主题转到另一个主题并拉取课程.我唯一的问题是有一个按钮查看更多课程"可以查看其余课程.有时你必须点击它几次，这就是我使用 while 循环的原因.但是 selenium 似乎没有执行这个点击.有谁知道为什么?

I am trying to pull out the names of all courses offered by Lynda.com together with the subject so that it appears on my list as '2D Drawing -- Project Soane: Recover a Lost Monument with BIM with Paul F. Aubin'. So I am trying to write a script that will go to each subject on http://www.lynda.com/sitemap/categories and pull out the list of courses. I already managed to get Selenium to go from one subject to another and pull the courses. My only problem is that there is a button 'See X more courses' to see the rest of the courses. Sometimes you have to click it couple of times that´s why I used while loop. But selenium doesn´t seem to execute this click. Does anyone know why?

这是我的代码:

from selenium import webdriver

url = 'http://www.lynda.com/sitemap/categories'

mydriver = webdriver.Chrome()
mydriver.get(url)

course_list = []

for a in [1,2,3]:
    for b in range(1,73):
        mydriver.find_element_by_xpath('//*[@id="main-content"]/div[2]/div[3]/div[%d]/ul/li[%d]/a' % (a,b)).click()
        while True:
        #click the button 'See more results' as long as it´s available
            try:
                mydriver.find_element_by_xpath('//*[@id="main-content"]/div[1]/div[3]/button').click()
            except:
                break
        subject = mydriver.find_element_by_tag_name('h1') # pull out the subject
        courses = mydriver.find_elements_by_tag_name('h3') # pull out the courses
        for course in courses:
            course_list.append(str(subject.text)+"  --  " + str(course.text))
        # go back to the initial site
        mydriver.get(url)

推荐答案

点击前滚动到元素:

see_more_results = browser.find_element_by_css_selector('button[class*=see-more-results]')
browser.execute_script('return arguments[0].scrollIntoView()', see_more_results)
see_more_results.click()

如何重复这些操作的一种解决方案可能是:

One solution how to repeat these actions could be:

def get_number_of_courses():
    return len(browser.find_elements_by_css_selector('.course-list > li'))

number_of_courses = get_number_of_courses()

while True:
    try:
        button = browser.find_element_by_css_selector(CSS_SELECTOR)
        browser.execute_script('return arguments[0].scrollIntoView()', button)
        button.click()

        while True:
            new_number_of_courses = get_number_of_courses()
            if (new_number_of_courses > number_of_courses):
                number_of_courses = new_number_of_courses
                break
    except:
        break

警告:使用内置显式等待总是比 while True 更好:
http://www.seleniumhq.org/docs/04_webdriver_advanced.jsp#explicit-waits

Caveat: it's always better to use build-in explicit wait than while True:
http://www.seleniumhq.org/docs/04_webdriver_advanced.jsp#explicit-waits

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