4

我正在尝试检索具有 ajax-load 向下滚动功能 alla Twitter 的页面中的元素。由于某种原因，这无法正常工作。我添加了一些打印语句来调试它，我总是得到相同数量的项目，然后函数返回。我在这里做错了什么？

wd = webdriver.Firefox()
wd.implicitly_wait(3)

def get_items(items):
    print len(items)
    wd.execute_script("window.scrollTo(0, document.body.scrollHeight);")
    # len(items) and len(wd.find_elements-by...()) both always seem to return the same number
    # if I were to start the loop with while True: it would work, but of course... never end
    while len(wd.find_elements_by_class_name('stream-item')) > len(items):
        items = wd.find_elements_by_class_name('stream-item')
        print items
        wd.execute_script("window.scrollTo(0, document.body.scrollHeight);")
    return items

def test():
    get_page('http://twitter.com/')
    get_items(wd.find_elements_by_class_name('stream-item'))
4

2 回答 2

4

试着在两者之间睡一觉

wd = webdriver.Firefox()
wd.implicitly_wait(3)

def get_items(items):
    print len(items)
    wd.execute_script("window.scrollTo(0, document.body.scrollHeight);")
    # len(items) and len(wd.find_elements-by...()) both always seem to return the same number
    # if I were to start the loop with while True: it would work, but of course... never end

    sleep(5) #seconds
    while len(wd.find_elements_by_class_name('stream-item')) > len(items):
        items = wd.find_elements_by_class_name('stream-item')
        print items
        wd.execute_script("window.scrollTo(0, document.body.scrollHeight);")
    return items

def test():
    get_page('http://twitter.com/')
    get_items(wd.find_elements_by_class_name('stream-item'))

注意：硬睡眠只是为了证明它有效。请改用 waits 包来等待智能条件。

于 2013-01-29T15:43:10.553 回答
0

while 循环中的条件是我的用例的问题。这是一个无限循环。我通过使用计数器解决了这个问题：

def get_items(items):

    item_nb = [0, 1] # initializing a counter of number of items found in page

    while(item_nb[-1] > item_nb[-2]):   # exiting the loop when no more new items can be found in the page

        items = wd.find_elements_by_class_name('stream-item')
        time.sleep(5)
        browser.execute_script("window.scrollTo(0, document.body.scrollHeight);")

        item_nb.append(len(items))

    return items

```

于 2017-10-21T11:29:25.263 回答