Selenium 显式等待与相对 XPath 定位器 [英] Selenium explicit wait with relative XPath locator

问题描述

在 Python 3.4 中使用 Selenium WebDriver.

Using Selenium WebDriver with Python 3.4.

我正在编写一个刮刀，并使​​用 XPath 相对于一些非根祖先元素定位元素，如下所示:

I'm writing a scraper, and locating elements using XPaths relative to some non-root ancestor element, such as below:

ancestor_element = driver.find_element_by_xpath(ancestor_xpath)
child_element = ancestor_element.find_element_by_xpath(child_xpath)

这按预期工作.但是，我不确定如何使用显式等待调用来执行此相对位置，因为我看到的示例使用以下语法:

This works as expected. However, I am unsure how to do this relative location with an explicit wait call, as the examples I have seen use this syntax:

child_element =  WebDriverWait(driver,10).until(
    EC.presence_of_element_located((By.XPATH, child_xpath))
)

它似乎根据页面根来评估 XPath，并抛出一个错误，抱怨 XPath 字符串的.//"开头.

which appears to evaluate the XPath against the page root, and throws an error complaining about the ".//" beginning of the XPath string.

对此有什么建议吗?

推荐答案

有同样的问题并遵循@Ron Norris 评论中的 lambda 示例.但是，文档并不清楚如何找到相对于 ancestor_element 的 child_element，即使在使用 lambda 时也是如此.

Had this same question and follow the lambda example from @Ron Norris's comment. However, the documentation isn't clear about how you can find the child_element relative to the ancestor_element, even when using lambda.

您实际上可以将 WebDriverWait 调用中的 driver 替换为您的 ancestor_element，以便显式地仅搜索 ancestor_element 下"的内容(尽管文档字符串声明它必须是 WebDriver 的实例，但我发现 WebElement 也可以使用).

You can actually replace driver in the WebDriverWait call with your ancestor_element, to explicitly only search things "under" the ancestor_element (even though the docstring states that it has to be an instance of WebDriver, I found that a WebElement also works).

所以我结束了类似的事情:

So I wound up with something like:

child_element =  WebDriverWait(ancestor_element,10).until(
    EC.presence_of_element_located((By.XPATH, child_xpath))
)

如果你想使用 lambda，你可以这样做:

If you want to use a lambda, you could then do:

child_element =  WebDriverWait(ancestor_element,10).until(
    lambda x: x.find_element_by_xpath(child_xpath)
)

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