Python crawler's Selenium set element wait method

1. Explicit wait

The WebDriverWait class is a wait method provided by WebDirver. In the set time, the default is to check whether the current page element exists once every 1 period of time, and if it cannot be detected beyond the set time, an exception will be thrown (TimeoutException)

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
import time

driver = webdriver.Chrome()
driver.get('https://www.baidu.com/')

element = WebDriverWait(driver, 5, 0.5).until(
      EC.presence_of_element_located((By.ID, "kw"))
      )
element.send_keys('selenium')
time.sleep(5)

driver.quit()

Syntax:

WebDriverWait (driver, timeout, poll_frequency=0. 5, ignored_exceptions=None). until (method, message= '')

The parameters are described as follows:

driver: Browser driver timeout: Maximum timeout, in seconds by default poll_frequency: The interval between detections, the default is 0.5 s ignored_exceptions: Exception information after timeout. NoSuchElementException exception is thrown by default until (method, message= ''): Call the driver provided by this method as a parameter until the return value is True until_not (method, message= ''): Call the driver provided by this method as a parameter until the return value is False presence_of_element_located (): Determines whether the element exists.

2. Implicit wait

from selenium import webdriver
from selenium.common.exceptions import NoSuchElementException
import time

driver = webdriver.Chrome()

#  Set implicit wait to 5 Seconds 
driver.implicitly_wait(5)
driver.get("http://www.baidu.com")

try:
 print(time.strftime('%Y-%m-%d %H:%M:%S'))
 driver.find_element_by_id("123456").send_keys('selenium') # Nonexistent id See the output error report and time 
 # driver.find_element_by_id("kw").send_keys('selenium') #  Existent id
except NoSuchElementException as e:
 print(e)
finally:
 print(time.strftime('%Y-%m-%d %H:%M:%S'))
 driver.quit()

implicitly_wait () defaults to 0, and the unit of the parameter is seconds. The waiting time set above is 5 seconds, which is not like time. sleep (5). When the execution process is located to an element, if the element can be located, continue to execute; If the element is not located, it will constantly determine whether the element is located in a loop. For example, if it is located in 1 second, if it runs directly down, an exception will be thrown if it exceeds the set time.

Selenium Collection Portal:

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