selenium基础用法（爬虫）
初识selenium
selenium最初是一个自动化测试工具,而爬虫中使用它主要是为了解决requests无法直接执行JavaScript代码的问题
selenium本质是通过驱动浏览器，完全模拟浏览器的操作，比如跳转、输入、点击、下拉等，来拿到网页渲染之后的结果，可支持多种浏览器
声明浏览器对象
from selenium import webdriver browser = webdriver.Chrome()
browser = webdriver.Firefox()
browser = webdriver.Edge()
browser = webdriver.PhantomJS()
browser = webdriver.Safari()
安装
#安装：selenium+chromedriver
pip3 install selenium
下载chromdriver.exe放到python安装路径的scripts目录中即可
国内镜像网站地址：http://npm.taobao.org/mirrors/chromedriver/2.29/
最新的版本去官网找:https://sites.google.com/a/chromium.org/chromedriver/downloads #安装：selenium+phantomjs
pip3 install selenium
下载phantomjs，解压后把phantomjs.exe所在的bin目录放到环境变量
下载链接：http://phantomjs.org/download.html #注意：
selenium3默认支持的webdriver是Firfox，而Firefox需要安装geckodriver
下载链接：https://github.com/mozilla/geckodriver/releases
基本使用
from selenium import webdriver
from selenium.webdriver.common.by import By
from selenium.webdriver.common.keys import Keys
from selenium.webdriver.support import expected_conditions as EC
from selenium.webdriver.support.wait import WebDriverWait browser = webdriver.Chrome()
try:
browser.get('https://www.baidu.com')
input = browser.find_element_by_id('kw')
input.send_keys('Python')
input.send_keys(Keys.ENTER)
wait = WebDriverWait(browser, 10)
wait.until(EC.presence_of_element_located((By.ID, 'content_left')))
print(browser.current_url)
print(browser.get_cookies())
print(browser.page_source)
finally:
browser.close()
访问页面
from selenium import webdriver browser = webdriver.Chrome()
browser.get('https://www.taobao.com')
print(browser.page_source)
browser.close()
查找元素
单个元素
from selenium import webdriver browser = webdriver.Chrome()
browser.get('https://www.taobao.com')
input_first = browser.find_element_by_id('q')
input_second = browser.find_element_by_css_selector('#q')
input_third = browser.find_element_by_xpath('//*[@id="q"]')
print(input_first, input_second, input_third)
browser.close()
<selenium.webdriver.remote.webelement.WebElement (session="5e53d9e1c8646e44c14c1c2880d424af", element="0.5649563096161541-1")> <selenium.webdriver.remote.webelement.WebElement (session="5e53d9e1c8646e44c14c1c2880d424af", element="0.5649563096161541-1")> <selenium.webdriver.remote.webelement.WebElement (session="5e53d9e1c8646e44c14c1c2880d424af", element="0.5649563096161541-1")>
output
- find_element_by_name
- find_element_by_xpath
- find_element_by_link_text
- find_element_by_partial_link_text
- find_element_by_tag_name
- find_element_by_class_name
- find_element_by_css_selector
from selenium import webdriver
from selenium.webdriver.common.by import By browser = webdriver.Chrome()
browser.get('https://www.taobao.com')
input_first = browser.find_element(By.ID, 'q')
print(input_first)
browser.close()
<selenium.webdriver.remote.webelement.WebElement (session="1f209c0d11551c40d9d20ad964fef244", element="0.07914603542731591-1")>
多个元素
from selenium import webdriver browser = webdriver.Chrome()
browser.get('https://www.taobao.com')
lis = browser.find_elements_by_css_selector('.service-bd li')
print(lis)
browser.close()
[<selenium.webdriver.remote.webelement.WebElement (session="c26290835d4457ebf7d96bfab3740d19", element="0.09221044033125603-1")>, <selenium.webdriver.remote.webelement.WebElement (session="c26290835d4457ebf7d96bfab3740d19", element="0.09221044033125603-2")>, <selenium.webdriver.remote.webelement.WebElement (session="c26290835d4457ebf7d96bfab3740d19", element="0.09221044033125603-3")>, <selenium.webdriver.remote.webelement.WebElement (session="c26290835d4457ebf7d96bfab3740d19", element="0.09221044033125603-4")>, <selenium.webdriver.remote.webelement.WebElement (session="c26290835d4457ebf7d96bfab3740d19", element="0.09221044033125603-5")>, <selenium.webdriver.remote.webelement.WebElement (session="c26290835d4457ebf7d96bfab3740d19", element="0.09221044033125603-6")>, <selenium.webdriver.remote.webelement.WebElement (session="c26290835d4457ebf7d96bfab3740d19", element="0.09221044033125603-7")>, <selenium.webdriver.remote.webelement.WebElement (session="c26290835d4457ebf7d96bfab3740d19", element="0.09221044033125603-8")>, <selenium.webdriver.remote.webelement.WebElement (session="c26290835d4457ebf7d96bfab3740d19", element="0.09221044033125603-9")>, <selenium.webdriver.remote.webelement.WebElement (session="c26290835d4457ebf7d96bfab3740d19", element="0.09221044033125603-10")>, <selenium.webdriver.remote.webelement.WebElement (session="c26290835d4457ebf7d96bfab3740d19", element="0.09221044033125603-11")>, <selenium.webdriver.remote.webelement.WebElement (session="c26290835d4457ebf7d96bfab3740d19", element="0.09221044033125603-12")>, <selenium.webdriver.remote.webelement.WebElement (session="c26290835d4457ebf7d96bfab3740d19", element="0.09221044033125603-13")>, <selenium.webdriver.remote.webelement.WebElement (session="c26290835d4457ebf7d96bfab3740d19", element="0.09221044033125603-14")>, <selenium.webdriver.remote.webelement.WebElement (session="c26290835d4457ebf7d96bfab3740d19", element="0.09221044033125603-15")>, <selenium.webdriver.remote.webelement.WebElement (session="c26290835d4457ebf7d96bfab3740d19", element="0.09221044033125603-16")>]
output
from selenium import webdriver
from selenium.webdriver.common.by import By browser = webdriver.Chrome()
browser.get('https://www.taobao.com')
lis = browser.find_elements(By.CSS_SELECTOR, '.service-bd li')
print(lis)
browser.close()
[<selenium.webdriver.remote.webelement.WebElement (session="bca1503cd36be550e8dba984b55c5d0e", element="0.7914623408963901-1")>, <selenium.webdriver.remote.webelement.WebElement (session="bca1503cd36be550e8dba984b55c5d0e", element="0.7914623408963901-2")>, <selenium.webdriver.remote.webelement.WebElement (session="bca1503cd36be550e8dba984b55c5d0e", element="0.7914623408963901-3")>, <selenium.webdriver.remote.webelement.WebElement (session="bca1503cd36be550e8dba984b55c5d0e", element="0.7914623408963901-4")>, <selenium.webdriver.remote.webelement.WebElement (session="bca1503cd36be550e8dba984b55c5d0e", element="0.7914623408963901-5")>, <selenium.webdriver.remote.webelement.WebElement (session="bca1503cd36be550e8dba984b55c5d0e", element="0.7914623408963901-6")>, <selenium.webdriver.remote.webelement.WebElement (session="bca1503cd36be550e8dba984b55c5d0e", element="0.7914623408963901-7")>, <selenium.webdriver.remote.webelement.WebElement (session="bca1503cd36be550e8dba984b55c5d0e", element="0.7914623408963901-8")>, <selenium.webdriver.remote.webelement.WebElement (session="bca1503cd36be550e8dba984b55c5d0e", element="0.7914623408963901-9")>, <selenium.webdriver.remote.webelement.WebElement (session="bca1503cd36be550e8dba984b55c5d0e", element="0.7914623408963901-10")>, <selenium.webdriver.remote.webelement.WebElement (session="bca1503cd36be550e8dba984b55c5d0e", element="0.7914623408963901-11")>, <selenium.webdriver.remote.webelement.WebElement (session="bca1503cd36be550e8dba984b55c5d0e", element="0.7914623408963901-12")>, <selenium.webdriver.remote.webelement.WebElement (session="bca1503cd36be550e8dba984b55c5d0e", element="0.7914623408963901-13")>, <selenium.webdriver.remote.webelement.WebElement (session="bca1503cd36be550e8dba984b55c5d0e", element="0.7914623408963901-14")>, <selenium.webdriver.remote.webelement.WebElement (session="bca1503cd36be550e8dba984b55c5d0e", element="0.7914623408963901-15")>, <selenium.webdriver.remote.webelement.WebElement (session="bca1503cd36be550e8dba984b55c5d0e", element="0.7914623408963901-16")>]
output
- find_elements_by_name
- find_elements_by_xpath
- find_elements_by_link_text
- find_elements_by_partial_link_text
- find_elements_by_tag_name
- find_elements_by_class_name
- find_elements_by_css_selector
元素互交操作
对获取的元素调用交互方法
from selenium import webdriver
import time browser = webdriver.Chrome()
browser.get('https://www.taobao.com')
input = browser.find_element_by_id('q')
input.send_keys('iPhone')
time.sleep(1)
input.clear()
input.send_keys('iPad')
button = browser.find_element_by_class_name('btn-search')
button.click()
更多操作: http://selenium-python.readthedocs.io/api.html#module-selenium.webdriver.remote.webelement
交互动作
将动作附加到动作链中串行执行
from selenium import webdriver
from selenium.webdriver import ActionChains browser = webdriver.Chrome()
url = 'http://www.runoob.com/try/try.php?filename=jqueryui-api-droppable'
browser.get(url)
browser.switch_to.frame('iframeResult')
source = browser.find_element_by_css_selector('#draggable')
target = browser.find_element_by_css_selector('#droppable')
actions = ActionChains(browser)
actions.drag_and_drop(source, target)
actions.perform()
更多操作: http://selenium-python.readthedocs.io/api.html#module-selenium.webdriver.common.action_chains
执行JavaScript
from selenium import webdriver browser = webdriver.Chrome()
browser.get('https://www.zhihu.com/explore')
browser.execute_script('window.scrollTo(0, document.body.scrollHeight)')
browser.execute_script('alert("To Bottom")')
获取元素信息
获取属性
from selenium import webdriver
from selenium.webdriver import ActionChains browser = webdriver.Chrome()
url = 'https://www.zhihu.com/explore'
browser.get(url)
logo = browser.find_element_by_id('zh-top-link-logo')
print(logo)
print(logo.get_attribute('class'))
<selenium.webdriver.remote.webelement.WebElement (session="5a9e00352fbb1bb3df8b81a9f666cba9", element="0.7456057855126614-1")>
zu-top-link-logo
output
获取文本
from selenium import webdriver browser = webdriver.Chrome()
url = 'https://www.zhihu.com/explore'
browser.get(url)
input = browser.find_element_by_class_name('zu-top-add-question')
print(input.text)
提问
获取ID、位置、标签名、大小
from selenium import webdriver browser = webdriver.Chrome()
url = 'https://www.zhihu.com/explore'
browser.get(url)
input = browser.find_element_by_class_name('zu-top-add-question')
print(input.id)
print(input.location)
print(input.tag_name)
print(input.size)
0.6822924344980397-
{'y': , 'x': }
button
{'height': , 'width': }
Frame
import time
from selenium import webdriver
from selenium.common.exceptions import NoSuchElementException browser = webdriver.Chrome()
url = 'http://www.runoob.com/try/try.php?filename=jqueryui-api-droppable'
browser.get(url)
browser.switch_to.frame('iframeResult')
source = browser.find_element_by_css_selector('#draggable')
print(source)
try:
logo = browser.find_element_by_class_name('logo')
except NoSuchElementException:
print('NO LOGO')
browser.switch_to.parent_frame()
logo = browser.find_element_by_class_name('logo')
print(logo)
print(logo.text)
<selenium.webdriver.remote.webelement.WebElement (session="4bb8ac03ced4ecbdefef03ffdc0e4ccd", element="0.44746093888932004-1")>
NO LOGO
<selenium.webdriver.remote.webelement.WebElement (session="4bb8ac03ced4ecbdefef03ffdc0e4ccd", element="0.13792611320464965-2")>
RUNOOB.COM
output
等待
隐式等待
当使用了隐式等待执行测试的时候，如果 WebDriver没有在 DOM中找到元素，将继续等待，超出设定时间后则抛出找不到元素的异常, 换句话说，当查找元素或元素并没有立即出现的时候，隐式等待将等待一段时间再查找 DOM，默认的时间是0
from selenium import webdriver browser = webdriver.Chrome()
browser.implicitly_wait(10)
browser.get('https://www.zhihu.com/explore')
input = browser.find_element_by_class_name('zu-top-add-question')
print(input)
<selenium.webdriver.remote.webelement.WebElement (session="b29214772d59e912f1ac52e96ed29abe", element="0.12886805191194894-1")>
output
显示等待
from selenium import webdriver
from selenium.webdriver.common.by import By
from selenium.webdriver.support.ui import WebDriverWait
from selenium.webdriver.support import expected_conditions as EC browser = webdriver.Chrome()
browser.get('https://www.taobao.com/')
wait = WebDriverWait(browser, 10)
input = wait.until(EC.presence_of_element_located((By.ID, 'q')))
button = wait.until(EC.element_to_be_clickable((By.CSS_SELECTOR, '.btn-search')))
print(input, button)
<selenium.webdriver.remote.webelement.WebElement (session="07dd2fbc2d5b1ce40e82b9754aba8fa8", element="0.5642646294074107-1")> <selenium.webdriver.remote.webelement.WebElement (session="07dd2fbc2d5b1ce40e82b9754aba8fa8", element="0.5642646294074107-2")>
output
- title_is 标题是某内容
- title_contains 标题包含某内容
- presence_of_element_located 元素加载出，传入定位元组，如(By.ID, 'p')
- visibility_of_element_located 元素可见，传入定位元组
- visibility_of 可见，传入元素对象
- presence_of_all_elements_located 所有元素加载出
- text_to_be_present_in_element 某个元素文本包含某文字
- text_to_be_present_in_element_value 某个元素值包含某文字
- frame_to_be_available_and_switch_to_it frame加载并切换
- invisibility_of_element_located 元素不可见
- element_to_be_clickable 元素可点击
- staleness_of 判断一个元素是否仍在DOM，可判断页面是否已经刷新
- element_to_be_selected 元素可选择，传元素对象
- element_located_to_be_selected 元素可选择，传入定位元组
- element_selection_state_to_be 传入元素对象以及状态，相等返回True，否则返回False
- element_located_selection_state_to_be 传入定位元组以及状态，相等返回True，否则返回False
- alert_is_present 是否出现Alert
详细内容：http://selenium-python.readthedocs.io/api.html#module-selenium.webdriver.support.expected_conditions
前进后退
import time
from selenium import webdriver browser = webdriver.Chrome()
browser.get('https://www.baidu.com/')
browser.get('https://www.taobao.com/')
browser.get('https://www.python.org/')
browser.back()
time.sleep(1)
browser.forward()
browser.close()
Cookies
from selenium import webdriver browser = webdriver.Chrome()
browser.get('https://www.zhihu.com/explore')
print(browser.get_cookies())
browser.add_cookie({'name': 'name', 'domain': 'www.zhihu.com', 'value': 'germey'})
print(browser.get_cookies())
browser.delete_all_cookies()
print(browser.get_cookies())
[{'secure': False, 'value': '"NGM0ZTM5NDAwMWEyNDQwNDk5ODlkZWY3OTkxY2I0NDY=|1491604091|236e34290a6f407bfbb517888849ea509ac366d0"', 'domain': '.zhihu.com', 'path': '/', 'httpOnly': False, 'name': 'l_cap_id', 'expiry': 1494196091.403418}, {'secure': False, 'value': '"YWEyOGY4MmI1MzQ2NGY5MmFiMjgzZGUzZWJjYTgwYjY=|1491604091|ff946847ddb5881245bdb7a5e6401b70dc61013f"', 'domain': '.zhihu.com', 'path': '/', 'httpOnly': False, 'name': 'cap_id', 'expiry': 1494196091.402855}, {'secure': False, 'value': '', 'domain': '.zhihu.com', 'path': '/', 'httpOnly': False, 'name': 'l_n_c'}, {'secure': False, 'value': '"MjcxMDE3YzU1YjI4NDljZjljNTQ4ZDIyOWJjZTBhNmY=|1491604091|8da4722b56a1545c2020dba97394a220c0eca8d9"', 'domain': '.zhihu.com', 'path': '/', 'httpOnly': False, 'name': 'r_cap_id', 'expiry': 1494196091.402525}, {'secure': False, 'value': '', 'domain': '.zhihu.com', 'path': '/', 'httpOnly': False, 'name': '__utmc'}, {'secure': False, 'value': '"AADCo7e1kguPTqvEOMieRUzwkA7ZUBhV-VY=|1491604091"', 'domain': '.zhihu.com', 'path': '/', 'httpOnly': False, 'name': 'd_c0', 'expiry': 1586212091.344773}, {'secure': False, 'value': '51854390.1491604091.1.1.utmcsr=(direct)|utmccn=(direct)|utmcmd=(none)', 'domain': '.zhihu.com', 'path': '/', 'httpOnly': False, 'name': '__utmz', 'expiry': }, {'secure': False, 'value': '3cc99fc5-8706-43fc-90ac-3ad991bd1a25', 'domain': '.zhihu.com', 'path': '/', 'httpOnly': False, 'name': '_zap', 'expiry': }, {'secure': False, 'value': '97cb00128ccb46659728f7c69cc191b0|1491604091000|1491604091000', 'domain': '.zhihu.com', 'path': '/', 'httpOnly': False, 'name': 'q_c1', 'expiry': 1586212091.401644}, {'secure': False, 'value': '51854390.2.10.1491604091', 'domain': '.zhihu.com', 'path': '/', 'httpOnly': False, 'name': '__utmb', 'expiry': }, {'secure': False, 'value': '', 'domain': '.zhihu.com', 'path': '/', 'httpOnly': False, 'name': 'n_c'}, {'secure': False, 'value': '51854390.000--|3=entry_date=20170408=1', 'domain': '.zhihu.com', 'path': '/', 'httpOnly': False, 'name': '__utmv', 'expiry': }, {'secure': False, 'value': '51854390.669300758.1491604091.1491604091.1491604091.1', 'domain': '.zhihu.com', 'path': '/', 'httpOnly': False, 'name': '__utma', 'expiry': }, {'secure': False, 'value': '', 'domain': '.zhihu.com', 'path': '/', 'httpOnly': False, 'name': '__utmt', 'expiry': }, {'secure': False, 'value': 'AQAAALCZuwh+dgIAeu3PPHA+csDPnXvT', 'domain': 'www.zhihu.com', 'path': '/', 'httpOnly': True, 'name': 'aliyungf_tc'}]
[{'secure': False, 'value': 'germey', 'domain': '.www.zhihu.com', 'path': '/', 'httpOnly': False, 'name': 'name'}, {'secure': False, 'value': '"NGM0ZTM5NDAwMWEyNDQwNDk5ODlkZWY3OTkxY2I0NDY=|1491604091|236e34290a6f407bfbb517888849ea509ac366d0"', 'domain': '.zhihu.com', 'path': '/', 'httpOnly': False, 'name': 'l_cap_id', 'expiry': 1494196091.403418}, {'secure': False, 'value': '"YWEyOGY4MmI1MzQ2NGY5MmFiMjgzZGUzZWJjYTgwYjY=|1491604091|ff946847ddb5881245bdb7a5e6401b70dc61013f"', 'domain': '.zhihu.com', 'path': '/', 'httpOnly': False, 'name': 'cap_id', 'expiry': 1494196091.402855}, {'secure': False, 'value': '', 'domain': '.zhihu.com', 'path': '/', 'httpOnly': False, 'name': 'l_n_c'}, {'secure': False, 'value': '"MjcxMDE3YzU1YjI4NDljZjljNTQ4ZDIyOWJjZTBhNmY=|1491604091|8da4722b56a1545c2020dba97394a220c0eca8d9"', 'domain': '.zhihu.com', 'path': '/', 'httpOnly': False, 'name': 'r_cap_id', 'expiry': 1494196091.402525}, {'secure': False, 'value': '', 'domain': '.zhihu.com', 'path': '/', 'httpOnly': False, 'name': '__utmc'}, {'secure': False, 'value': '"AADCo7e1kguPTqvEOMieRUzwkA7ZUBhV-VY=|1491604091"', 'domain': '.zhihu.com', 'path': '/', 'httpOnly': False, 'name': 'd_c0', 'expiry': 1586212091.344773}, {'secure': False, 'value': '51854390.1491604091.1.1.utmcsr=(direct)|utmccn=(direct)|utmcmd=(none)', 'domain': '.zhihu.com', 'path': '/', 'httpOnly': False, 'name': '__utmz', 'expiry': }, {'secure': False, 'value': '3cc99fc5-8706-43fc-90ac-3ad991bd1a25', 'domain': '.zhihu.com', 'path': '/', 'httpOnly': False, 'name': '_zap', 'expiry': }, {'secure': False, 'value': '97cb00128ccb46659728f7c69cc191b0|1491604091000|1491604091000', 'domain': '.zhihu.com', 'path': '/', 'httpOnly': False, 'name': 'q_c1', 'expiry': 1586212091.401644}, {'secure': False, 'value': '51854390.2.10.1491604091', 'domain': '.zhihu.com', 'path': '/', 'httpOnly': False, 'name': '__utmb', 'expiry': }, {'secure': False, 'value': '', 'domain': '.zhihu.com', 'path': '/', 'httpOnly': False, 'name': 'n_c'}, {'secure': False, 'value': '51854390.000--|3=entry_date=20170408=1', 'domain': '.zhihu.com', 'path': '/', 'httpOnly': False, 'name': '__utmv', 'expiry': }, {'secure': False, 'value': '51854390.669300758.1491604091.1491604091.1491604091.1', 'domain': '.zhihu.com', 'path': '/', 'httpOnly': False, 'name': '__utma', 'expiry': }, {'secure': False, 'value': '', 'domain': '.zhihu.com', 'path': '/', 'httpOnly': False, 'name': '__utmt', 'expiry': }, {'secure': False, 'value': 'AQAAALCZuwh+dgIAeu3PPHA+csDPnXvT', 'domain': 'www.zhihu.com', 'path': '/', 'httpOnly': True, 'name': 'aliyungf_tc'}]
[]
output
选项卡管理
import time
from selenium import webdriver browser = webdriver.Chrome()
browser.get('https://www.baidu.com')
browser.execute_script('window.open()')
print(browser.window_handles)
browser.switch_to_window(browser.window_handles[1])
browser.get('https://www.taobao.com')
time.sleep(1)
browser.switch_to_window(browser.window_handles[0])
browser.get('https://python.org')
['CDwindow-4f58e3a7-7167-4587-bedf-9cd8c867f435', 'CDwindow-6e05f076-6d77-453a-a36c-32baacc447df']
output
异常处理
from selenium import webdriver browser = webdriver.Chrome()
browser.get('https://www.baidu.com')
browser.find_element_by_id('hello')
NoSuchElementException Traceback (most recent call last)
<ipython-input--978945848a1b> in <module>()
browser = webdriver.Chrome()
browser.get('https://www.baidu.com')
----> browser.find_element_by_id('hello') /Library/Frameworks/Python.framework/Versions/3.5/lib/python3./site-packages/selenium/webdriver/remote/webdriver.py in find_element_by_id(self, id_)
driver.find_element_by_id('foo')
"""
--> return self.find_element(by=By.ID, value=id_) def find_elements_by_id(self, id_): /Library/Frameworks/Python.framework/Versions/3.5/lib/python3./site-packages/selenium/webdriver/remote/webdriver.py in find_element(self, by, value)
return self.execute(Command.FIND_ELEMENT, {
'using': by,
--> 'value': value})['value'] def find_elements(self, by=By.ID, value=None): /Library/Frameworks/Python.framework/Versions/3.5/lib/python3./site-packages/selenium/webdriver/remote/webdriver.py in execute(self, driver_command, params)
response = self.command_executor.execute(driver_command, params)
if response:
--> self.error_handler.check_response(response)
response['value'] = self._unwrap_value(
response.get('value', None)) /Library/Frameworks/Python.framework/Versions/3.5/lib/python3./site-packages/selenium/webdriver/remote/errorhandler.py in check_response(self, response)
elif exception_class == UnexpectedAlertPresentException and 'alert' in value:
raise exception_class(message, screen, stacktrace, value['alert'].get('text'))
--> raise exception_class(message, screen, stacktrace) def _value_or_default(self, obj, key, default): NoSuchElementException: Message: no such element: Unable to locate element: {"method":"id","selector":"hello"}
(Session info: chrome=57.0.2987.133)
(Driver info: chromedriver=2.27. (e97a722caafc2d3a8b807ee115bfb307f7d2cfd9),platform=Mac OS X 10.12. x86_64)
异常
from selenium import webdriver
from selenium.common.exceptions import TimeoutException, NoSuchElementException browser = webdriver.Chrome()
try:
browser.get('https://www.baidu.com')
except TimeoutException:
print('Time Out')
try:
browser.find_element_by_id('hello')
except NoSuchElementException:
print('No Element')
finally:
browser.close()
No Element
详细文档：http://selenium-python.readthedocs.io/api.html#module-selenium.common.exceptions
selenium基础用法（爬虫）的更多相关文章
- 【Python爬虫】selenium基础用法
selenium 基础用法 阅读目录 初识selenium 基本使用 查找元素 元素互交操作 执行JavaScript 获取元素信息 等待 前进后退 Cookies 选项卡管理 异常处理 初识sele ...
- 爬虫简介、requests 基础用法、urlretrieve()
1. 爬虫简介 2. requests 基础用法 3. urlretrieve() 1. 爬虫简介 爬虫的定义 网络爬虫(又被称为网页蜘蛛.网络机器人),是一种按照一定的规则,自动地抓取万维网信息的程 ...
- 使用Python + Selenium打造浏览器爬虫
Selenium 是一款强大的基于浏览器的开源自动化测试工具,最初由 Jason Huggins 于 2004 年在 ThoughtWorks 发起,它提供了一套简单易用的 API,模拟浏览器的各种操 ...
- Python+Selenium基础入门及实践
Python+Selenium基础入门及实践 32018.08.29 11:21:52字数 3220阅读 23422 一.Selenium+Python环境搭建及配置 1.1 selenium 介绍 ...
- asyncio 基础用法
asyncio 基础用法 python也是在python 3.4中引入了协程的概念.也通过这次整理更加深刻理解这个模块的使用 asyncio 是干什么的? asyncio是Python 3.4版本引入 ...
- PropertyGrid控件由浅入深(二)：基础用法
目录 PropertyGrid控件由浅入深(一):文章大纲 PropertyGrid控件由浅入深(二):基础用法 控件的外观构成 控件的外观构成如下图所示: PropertyGrid控件包含以下几个要 ...
- logstash安装与基础用法
若是搭建elk,建议先安装好elasticsearch 来自官网,版本为2.3 wget -c https://download.elastic.co/logstash/logstash/packag ...
- elasticsearch安装与基础用法
来自官网,版本为2.3 注意elasticsearch依赖jdk,2.3依赖jdk7 下载rpm包并安装 wget -c https://download.elastic.co/elasticsear ...
- BigDecimal最基础用法
BigDecimal最基础用法 用字符串生成的BigDecimal是不会丢精度的. 简单除法. public class DemoBigDecimal { public static void mai ...
随机推荐
- linux存储管理之基本分区
基本分区管理 ====================================================================================基本分区(MBR| ...
- PostgreSQL work_mem理解
官方说法: work_mem (integer) Specifies the amount of memory to be used by internal sort operations and h ...
- 百度地图API---JS开发
百度地图API 开源地址:http://lbsyun.baidu.com/index.php?title=jspopular/guide/introduction#Https_.E8.AF.B4.E6 ...
- 牛客网多校第3场C-shuffle card 平衡树或stl（rope）
链接:https://www.nowcoder.com/acm/contest/141/C 来源:牛客网 题目描述 Eddy likes to play cards game since there ...
- LoadRunner遇到的错误及解决方法
1.返回的报文太长: intweb_set_max_html_param_len(const char * length); intweb_set_max_html_param_len(") ...
- excel表格中，怎么根据一列重复的数据求对应另一列总和
如下: 求出姓名对应分数总和对应 : 首先复制一份Sheet2 对Sheet1进行操作选中A列姓名 数据->删除重复项->以前选中区域排序->删除重复项 然后删除对应成绩项选中张三对 ...
- Awesome Tools
Awesome R: https://awesome-r.com/ (Chinese translation: http://www.ppvke.com/Blog/archives/40981) Aw ...
- VS2017调试技巧
Visual Studio的调试技巧 调试技巧是衡量程序员水平的一个重要指标.掌握好的调试技巧与工具的使用方法,也是非常重要的.*** 演示环境: VS2017C#*** 演示用的代码: publ ...
- HTTP的缓存策略
etag 与 if-match https://www.cnblogs.com/huangzhilong/p/4999207.html https://juejin.im/post/5c136bd16 ...
- 原生js手风琴效果
//js代码 //获取li var list = document.getElementsByTagName("li")[0]; //遍历 排他 for( var i=0;i&l ...