python selenium xpath/css选择器

Question

我正在尝试使用xpath或css选择器来选择特定的信息。但是我一直收到错误信息。有人能帮我看看哪里出问题了吗？

这是我代码的一部分

output = driver.find_element_by_xpath("//td[@class_= 'sku']")
print(output)

---

根据下面的修改，我收到了这个错误信息：

Traceback (most recent call last):
  File "sa.py", line 25, in <module>
    output = driver.find_element_by_xpath("//td[@cl
  File "C:\Python27\lib\site-packages\selenium\webd
   return self.find_element(by=By.XPATH, value=xpa
  File "C:\Python27\lib\site-packages\selenium\webd
    {'using': by, 'value': value})['value']
  File "C:\Python27\lib\site-packages\selenium\webd
    self.error_handler.check_response(response)
  File "C:\Python27\lib\site-packages\selenium\webd
    raise exception_class(message, screen, stacktra
selenium.common.exceptions.NoSuchElementException:
td[@class=\'sku\']/p"}' ; Stacktrace:
    at FirefoxDriver.prototype.findElementInternal_
ver@googlecode.com/components/driver_component.js:9
    at FirefoxDriver.prototype.findElement (file://
ecode.com/components/driver_component.js:9479)
    at DelayedCommand.prototype.executeInternal_/h
er@googlecode.com/components/command_processor.js:1
    at DelayedCommand.prototype.executeInternal_ (f
@googlecode.com/components/command_processor.js:114
    at DelayedCommand.prototype.execute/< (file:///
code.com/components/command_processor.js:11402)

---

这是我写的代码：

from selenium import webdriver
from selenium.common.exceptions import TimeoutException
from selenium.webdriver.support.ui import WebDriverWait
from selenium.webdriver.support import expected_conditions as EC

url = "http://www.sigmaaldrich.com/united-states.html"
#cas = "1300746-79-5"
cas = "100-44-7"

driver = webdriver.Firefox()
driver.get(url)

inputElement = driver.find_element_by_name("Query")
inputElement.send_keys(cas)
inputElement.submit()

pricing_link = driver.find_element_by_css_selector("li.priceValue a")
pricing_link.click()

output = driver.find_element_by_xpath("//td[@class='sku']/p") 
print(output)

driver.quit()

Answer 1

经过与提问者和alecxe的讨论，这个问题是因为时间上的问题。你需要使用WebDriverWait来等待表格加载完成。

# XPath to select <p> inside <td> with class name 'sku'
outputs_by_xpath = WebDriverWait(driver, 10).until(
    lambda driver : driver.find_elements_by_xpath(".//td[@class='sku']/p")
)

# or CSS selector
outputs_by_css = WebDriverWait(driver, 10).until(
    lambda driver : driver.find_elements_by_css_selector("td.sku > p")
)

for output in outputs_by_xpath:
    print(output.text)

print("\n")

for output in outputs_by_css:
    print(output.text)

输出结果：

185558-50G
185558-250G
185558-1KG
185558-2KG

185558-50G
185558-250G
185558-1KG
185558-2KG