我正在尝试用Selenium打印YouTube视频的标题。我尝试了三种不同的方法，但只有一种方法有效。所以我只想知道为什么其他方法不起作用。
我的第一次尝试：
videoTitle = driver.find_element_by_css_selector("yt-formatted-string.style-scope ytd-video-primary-info-renderer")
print(videoTitle)
这不起作用，错误是：
File "C:UsersforreIdeaProjectsPythonNotesPackagesSeleniumWeb_Scraping.py", line 21, in <module>
videoTitle = driver.find_element_by_xpath("/html/body/ytd-app/div/ytd-page-manager/ytd-watch-flexy/div[5]/div[1]/div/div[8]/div[2]/ytd-video-primary-info-renderer/div/h1/yt-formatted-string")
File "C:UsersforreAppDataLocalProgramsPythonPython39libsite-packagesseleniumwebdriverremotewebdriver.py", line 520, in find_element_by_xpath
return self.find_element(by=By.XPATH, value=xpath)
File "C:UsersforreAppDataLocalProgramsPythonPython39libsite-packagesseleniumwebdriverremotewebdriver.py", line 1244, in find_element
return self.execute(Command.FIND_ELEMENT, {
File "C:UsersforreAppDataLocalProgramsPythonPython39libsite-packagesseleniumwebdriverremotewebdriver.py", line 424, in execute
self.error_handler.check_response(response)
File "C:UsersforreAppDataLocalProgramsPythonPython39libsite-packagesseleniumwebdriverremoteerrorhandler.py", line 247, in check_response
raise exception_class(message, screen, stacktrace)
selenium.common.exceptions.NoSuchElementException: Message: no such element: Unable to locate element: {"method":"xpath","selector":"/html/body/ytd-app/div/ytd-page-manager/ytd-watch-flexy/div[5]/div[1]/div/div[8]/div[2]/ytd-video-primary-info-renderer/div/h1/yt-formatted-string"}
(Session info: chrome=96.0.4664.110)
Stacktrace:
Backtrace:
Ordinal0 [0x002C6903+2517251]
Ordinal0 [0x0025F8E1+2095329]
Ordinal0 [0x00162848+1058888]
Ordinal0 [0x0018D448+1233992]
Ordinal0 [0x0018D63B+1234491]
Ordinal0 [0x001B7812+1406994]
Ordinal0 [0x001A650A+1336586]
Ordinal0 [0x001B5BBF+1399743]
Ordinal0 [0x001A639B+1336219]
Ordinal0 [0x001827A7+1189799]
Ordinal0 [0x00183609+1193481]
GetHandleVerifier [0x00455904+1577972]
GetHandleVerifier [0x00500B97+2279047]
GetHandleVerifier [0x00356D09+534521]
GetHandleVerifier [0x00355DB9+530601]
Ordinal0 [0x00264FF9+2117625]
Ordinal0 [0x002698A8+2136232]
Ordinal0 [0x002699E2+2136546]
Ordinal0 [0x00273541+2176321]
BaseThreadInitThunk [0x76136739+25]
RtlGetFullPathName_UEx [0x77D78AFF+1215]
RtlGetFullPathName_UEx [0x77D78ACD+1165]
(No symbol) [0x00000000]
Process finished with exit code 1
我的第二次尝试：
videoTitle = driver.find_element_by_xpath("/html/body/ytd-app/div/ytd-page-manager/ytd-watch-flexy/div[5]/div[1]/div/div[8]/div[2]/ytd-video-primary-info-renderer/div/h1/yt-formatted-string")
print(videoTitle)
这也不起作用，我也犯了同样的错误。
您首次尝试
videoTitle = driver.find_element_by_css_selector("yt-formatted-string.style-scope ytd-video-primary-info-renderer")
有3个问题：
yt-formatted-string.style-scope ytd-video-primary-info-renderer不是该元素的有效CSS选择器。两个字符串style-scope和ytd-video-primary-info-renderer是两个类属性值。为了使上面的表达式有效，您必须在每个表达式前面放一个点.，因为在CSS Selector中，值前面的点.表示这是一个类名- 因此，
yt-formatted-string.style-scope.ytd-video-primary-info-renderer将是一个正确的CSS选择器，但当您想要访问第二个时，它将匹配该页面上的3个元素
您可以使用find_elements_by_css_selector方法来执行此操作，访问列表中的第二个元素 - 您必须从web元素中提取文本
因此，要使用第一种方法获得YouTube视频标题，您的代码应该是：
videoTitle = driver.find_elements_by_css_selector("yt-formatted-string.style-scope ytd-video-primary-info-renderer")[1].text
关于/html/body/ytd-app/div/ytd-page-manager/ytd-watch-flexy/div[5]/div[1]/div/div[8]/div[2]/ytd-video-primary-info-renderer/div/h1/yt-formatted-string，您正在尝试使用一个绝对的XPath表达式。这种定位器非常脆弱。我试着使用它，但无法与此定位器匹配任何内容
您应该学习如何创建正确的XPath定位器
例如，这将是正确的XPath定位器：
"//h1//*[@class='style-scope ytd-video-primary-info-renderer']"
因此，这将起作用：
videoTitle = driver.find_element_by_xpath("//h1//*[@class='style-scope ytd-video-primary-info-renderer']").text
print(videoTitle)