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Selenium. Unable to locate element from the html website

Here's the link of the website I'm trying to scrape (I'm training for the moment, nothing fancy):
link
Here's my script, he's quite long but nothing too complicated :
from selenium import webdriver
if __name__ == "__main__":
print("Web Scraping application started")
PATH = "driver\chromedriver.exe"
options = webdriver.ChromeOptions()
options.add_argument("--disable-gpu")
options.add_argument("--window-size=1200,900")
options.add_argument('enable-logging')
driver = webdriver.Chrome(options=options, executable_path=PATH)
driver.get('https://fr.hotels.com/')
driver.maximize_window()
destination_location_element = driver.find_element_by_id("qf-0q-destination")
check_in_date_element = driver.find_element_by_id("qf-0q-localised-check-in")
check_out_date_element = driver.find_element_by_id("qf-0q-localised-check-out")
search_button_element = driver.find_element_by_xpath('//*[#id="hds-marquee"]/div[2]/div[1]/div/form/div[4]/button')
print('Printing type of search_button_element')
print(type(search_button_element))
destination_location_element.send_keys('Paris')
check_in_date_element.clear()
check_in_date_element.send_keys("29/05/2021")
check_out_date_element.clear()
check_out_date_element.send_keys("30/05/2021")
close_date_window = driver.find_element_by_xpath('/html/body/div[7]/div[4]/button')
print('Printing type of close_date_window')
print(type(close_date_window))
close_date_window[0].click()
search_button_element.click()
time.sleep(10)
hotels = driver.find_element_by_class_name('hotel-wrap')
print("\n")
i = 1
for hotel in hotels:
try:
print(hotel.find_element_by_xpath('//*[#id="listings"]/ol/li['+str(i)+']/article/section/div/h3/a').text)
print(hotel.find_element_by_xpath('//*[#id="listings"]/ol/li[' + str(i) + ']/article/section/div/address/span').text)
except Exception as ex:
print(ex)
print('Failed to extract data from element.')
i = i +1
print('\n')
driver.close()
print('Web Scraping application completed')
And here's the error I get :
File "hotelscom.py", line 21, in <module>
destination_location_element = driver.find_element_by_id("qf-0q-destination")
selenium.common.exceptions.NoSuchElementException: Message: no such element: Unable to locate element: {"method":"css selector","selector":"[id="qf-0q-destination"]"}
(Session info: chrome=90.0.4430.85)
Any idea how to fix that ? I don't understand why it get me this error because in the html code, there is this syntax. But i guess I'm wrong.

You have multiple problems with your code and the site.
SITE PROBLEMS
1 The site is located on multiple servers and different servers have different html code. I do not know if it depends on location or not.
2 The version I have solution for has few serious bugs (or maybe those are features). Among them:
When you press Enter it starts hotels search when a date field is opened and and you just want to close this date field. So, it is a problem to close input fields in a traditional way.
clear() of Selenium does not work as it is supposed to work.
BUGS IN YOUR CODE
1 You are defining window size in options and you are maximizing the window immediately after site is opened. Use only one option
2 You are entering dates like "29/05/2021", but sites recognises formats only like: "05/30/2021". It is a big difference
3 You are not using any waits and they are extremely important.
4 Your locators are wrong and unstable. Even locators with id did not always work for me because if you will make a search, there are two elements for some of them. So I replaces them with css selectors.
Please note that my solution works only for an old version of site. If you want to a specific version to be opened you will need either:
Get the site by a direct ip address, like driver.get('site ip address')
Implement a strategy in your framework which recognises which site version is opened and applies inputs depending on it.
SOLUTION
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
if __name__ == "__main__":
print("Web Scraping application started")
options = webdriver.ChromeOptions()
options.add_argument("--disable-gpu")
options.add_argument("--window-size=1200,900")
options.add_argument('enable-logging')
driver = webdriver.Chrome(options=options, executable_path='/snap/bin/chromium.chromedriver')
driver.get('https://fr.hotels.com/')
wait = WebDriverWait(driver, 15)
wait.until(EC.element_to_be_clickable((By.CSS_SELECTOR, "#qf-0q-destination")))
destination_location_element = driver.find_element_by_css_selector("#qf-0q-destination")
destination_location_element.send_keys('Paris, France')
wait.until(EC.presence_of_all_elements_located((By.CSS_SELECTOR, ".widget-autosuggest.widget-autosuggest-visible table tr")))
destination_location_element.send_keys(Keys.TAB) # workaround to close destination field
driver.find_element_by_css_selector(".widget-query-sub-title").click()
wait.until(EC.invisibility_of_element_located((By.CSS_SELECTOR, ".widget-query-group.widget-query-destination [aria-expanded=true]")))
wait.until(EC.element_to_be_clickable((By.CSS_SELECTOR, "#qf-0q-localised-check-in")))
check_in_date_element = driver.find_element_by_css_selector("#qf-0q-localised-check-in")
check_in_date_element.send_keys(Keys.CONTROL, 'a') # workaround to replace clear() method
check_in_date_element.send_keys(Keys.DELETE) # workaround to replace clear() method
# check_in_date_element.click()
check_in_date_element.send_keys("05/30/2021")
# wait.until(EC.visibility_of_element_located((By.CSS_SELECTOR, "#qf-0q-localised-check-out")))
check_out_date_element = driver.find_element_by_id("qf-0q-localised-check-out")
check_out_date_element.click()
check_out_date_element.send_keys(Keys.CONTROL, 'a')
check_out_date_element.send_keys(Keys.DELETE)
check_out_date_element.send_keys("05/31/2021")
driver.find_element_by_css_selector(".widget-query-sub-title").click() # workaround to close end date
wait.until(EC.element_to_be_clickable((By.CSS_SELECTOR, "#hds-marquee button"))).click()
Spent on this few hours, the task seemed just interesting for me.
It works for this UI:
The code can still be optimised. It's up to you.
UPDATE:
I found out that the site has at least three home pages with three different Destination and other fields locators.
The easiest workaround that came into my mind is something like this:
try:
element = driver.find_element_by_css_selector("#qf-0q-destination")
if element.is_displayed():
wait.until(EC.element_to_be_clickable((By.CSS_SELECTOR, "#qf-0q-destination")))
destination_location_element = driver.find_element_by_css_selector("#qf-0q-destination")
print("making input to Destination field of site 1")
destination_location_element.send_keys('Paris, France')
# input following data
except:
print("Page 1 not found")
try:
element = driver.find_element_by_css_selector("input[name=q-destination-srs7]")
if element.is_displayed():
wait.until(EC.element_to_be_clickable((By.CSS_SELECTOR, "input[name=q-destination-srs7]")))
destination_location_element = driver.find_element_by_css_selector("input[name=q-destination-srs7]")
print("making input to Destination field of site 2")
destination_location_element.send_keys('Paris, France')
# input following data
except:
print("Page 2 is not found")
try:
element = driver.find_element_by_css_selector("form[method=GET]>div>._1yFrqc")
if element.is_displayed():
wait.until(EC.element_to_be_clickable((By.CSS_SELECTOR, "form[method=GET]>div>._1yFrqc")))
destination_location_element = driver.find_element_by_css_selector("form[method=GET]>div>._1yFrqc")
print("making input to Destination field of site 3")
destination_location_element.send_keys('Paris, France')
# input following data
except:
print("Page 3 is not found")
But the best solution would be to have a direct access to a specific server that has only one version available.
Please also note that if you access the site by a direct link for France: https://fr.hotels.com/?pos=HCOM_FR&locale=fr_FR your input dates will be as you initially specified, for example 30/05/2021.

Try this
driver.find_element_by_xpath(".//div[contains(#class,'destination')]/input[#name='q-destination']")
Also please add wait after you maximize the window

You are missing a wait / sleep before finding the element.
So, just add this:
element = WebDriverWait(driver, 20).until(
EC.element_to_be_clickable((By.ID, "qf-0q-destination")))
element.click()
to use this you will have to use the following imports:
from selenium.webdriver.common.by import By
from selenium.webdriver.support.ui import WebDriverWait
from selenium.webdriver.support import expected_conditions as E

Selenium(PYTHON) check whether or not element exists

So im trying to figure out how to run this loop properly, my issue is that depending on the link that is loading, the page that loads will have an access denied error, this isnt like that for all the links, my issue is that i would like to identify whether or not when a particular element loads onto my screen, the program recognizes it and breaks the loop, and starts the next iteration in the for loop, so im trying to determine whether the "Access-Denied" element is present, and if it is, then break, otherwise, continue the for loop
idList = ["8573", "85678", "2378", "2579"]
for ID in idList:
print(ID)
driver.get(f"https://www.someWebsite/username/{ID}")
element = driver.find_element_by_class_name("Access-Denied")
print("error loading website")
break
if not element:
print("you may continue the for loop")
Mind you if the element showing the access denied page isnt present, i get an error that the 'Access-denied' element doesnt exist, how can i fix this?

You want to wait for the webpage to receive the proper response. Using the following code, you can wait for the full response to load, and then take
appropriate action based on the outcome:
from selenium.webdriver.common.by import By
from selenium.common.exceptions import TimeoutException
from selenium.webdriver.support.ui import WebDriverWait
...
try:
_ = WebDriverWait(driver, 10).until(
EC.presence_of_element_located((By.CLASS_NAME, "Access-Denied"))
)
print("error loading website")
break
except TimeoutException:
print("you may continue the for loop")
...

So you want to loop through if the access denied is there then break.
wait = WebDriverWait(driver, 10)
idList = ["8573", "85678", "2378", "2579"]
for ID in idList:
print(ID)
driver.get(f"https://www.someWebsite/username/{ID}")
try:
element=wait.until(EC.presence_of_element_located((By.CLASS_NAME, 'Access-Denied')))
break
except:
continue
Import
from selenium.webdriver.common.by import By
from selenium.webdriver.support.ui import WebDriverWait
from selenium.webdriver.support import expected_conditions as EC

Keep refreshing page until element is clickable?

I am currently attempting to get my code to keep refreshing the page until a specific element on the website becomes clickable. Sample code is provided below:
lolSize = False
while not lolSize:
try:
if size.is_enabled():
driver.execute_script("arguments[0].click();", size)
lolSize = True
except:
time.sleep(1)
driver.refresh()
Now if I put a value that is clickable at the exact moment of running the code, it works just fine. However, if a value that isn't clickable at the moment is used, the page does not refresh at all. Apologies if something rudimentary is incorrect with my code, I'm very much a novice in Python. Any help is appreciated, and if you need clarification regarding my issue, don't hesitate to ask! Thank you! :)

You must handle the else condition of your if statement
while not lolSize:
try:
assert size.is_enabled()
driver.execute_script("arguments[0].click();", size)
lolSize = True
except:
time.sleep(1)
driver.refresh()
The assert will raise an exception if it is not true and refresh will occur in the exception handler code.
Also, I believe with the code provided, upon refresh the is_enabled() code will always raise an exception. You need to retrieve the size element each refresh to not have a staleElementException. Such exception will loop your code with driver.refresh() each time.
UPDATE
To ensure there is no element clickable, use the WebDriverWait to get time to find the element
from selenium.webdriver.support import expected_conditions as EC
from selenium.webdriver.support.wait import WebDriverWait
from selenium.webdriver.common.by import By
timeout_in_sec = 5. # how much time to check for a clickable element
wait = WebDriverWait(driver, timeout_in_sec)
wait.until(EC.element_to_be_clickable((By.CSS_SELECTOR, 'yourCssPath')))
With code updated that gives:
wait = WebDriverWait(driver, timeout_in_sec)
while not lolSize:
try:
size = wait.until(EC.element_to_be_clickable((By.CSS_SELECTOR, 'yourCssPath')))
driver.execute_script("arguments[0].click();", size)
lolSize = True
except:
time.sleep(1)
driver.refresh()
Note that (By.CSS_SELECTOR, 'yourCssPath') needs to match the way you previously found size

My idea for this problem would be like that :
while True:
try:
driver.execute_script("arguments[0].click();")
break
except:
time.sleep(1)
driver.refresh()

StaleElementReferenceException in Python

I am trying to scrape data from the Sunshine List website (http://www.sunshinelist.ca/) using the Selenium package but I get the following error mentioned below. From several other related posts I understand that I need to use the WebDriverWait to explicitly ask the driver to wait/refresh but I am unable to identify where and how I should call the function.
Screenshot of Error
StaleElementReferenceException: Message: The element reference
of (tr class="even") stale: either the element is no longer attached to the DOM or the
page has been refreshed
import numpy as np
import pandas as pd
import requests
import time
from bs4 import BeautifulSoup
from selenium import webdriver
from selenium.common.exceptions import NoSuchElementException
from selenium.webdriver.firefox.firefox_binary import FirefoxBinary
from selenium.webdriver.common.desired_capabilities import DesiredCapabilities
from selenium.webdriver.common.keys import Keys
from selenium.webdriver.support.ui import WebDriverWait
from selenium.common.exceptions import StaleElementReferenceException
from selenium.webdriver.support import expected_conditions as EC
from selenium.webdriver.common.by import By
ffx_bin = FirefoxBinary(r'C:\Users\BhagatM\AppData\Local\Mozilla Firefox\firefox.exe')
ffx_caps = DesiredCapabilities.FIREFOX
ffx_caps['marionette'] = True
driver = webdriver.Firefox(capabilities=ffx_caps,firefox_binary=ffx_bin)
driver.get("http://www.sunshinelist.ca/")
driver.maximize_window()
tablewotags1=[]
while True:
divs = driver.find_element_by_id('datatable-disclosures')
divs1=divs.find_elements_by_tag_name('tbody')
for d1 in divs1:
div2=d1.find_elements_by_tag_name('tr')
for d2 in div2:
tablewotags1.append(d2.text)
try:
driver.find_element_by_link_text('Next →').click()
except NoSuchElementException:
break
year1=tablewotags1[0::10]
name1=tablewotags1[3::10]
position1=tablewotags1[4::10]
employer1=tablewotags1[1::10]
df1=pd.DataFrame({'Year':year1,'Name':name1,'Position':position1,'Employer':employer1})
df1.to_csv('Sunshine List-1.csv', index=False)

If your problem is to click the "Next" button, you can do that with the xpath:
driver = webdriver.Firefox(executable_path=r'/pathTo/geckodriver')
driver.get("http://www.sunshinelist.ca/")
wait = WebDriverWait(driver, 20)
el=wait.until(EC.presence_of_element_located((By.XPATH,"//ul[#class='pagination']/li[#class='next']/a[#href='#' and text()='Next → ']")))
el.click()

For each click on the "Next" button -- you should find that button and click on it.
Or do something like this:
max_attemps = 10
while True:
next = self.driver.find_element_by_css_selector(".next>a")
if next is not None:
break
else:
time.sleep(0.5)
max_attemps -= 1
if max_attemps == 0:
self.fail("Cannot find element.")
And after this code does click action.
PS: Also try to add just time.sleep(x) after fiding element and then do click action.

Try this code below.
When the element is no longer attached to the DOM and the StaleElementReferenceException is invoked, search for the element again to reference the element.
Please do note I checked with Chrome:
try:
driver.find_element_by_css_selector('div[id="datatable-disclosures_wrapper"] li[class="next"]>a').click()
except StaleElementReferenceException:
driver.find_element_by_css_selector('div[id="datatable-disclosures_wrapper"] li[class="next"]>a').click()
except NoSuchElementException:
break

>>>Stale Exceptions can be handled using **StaleElementReferenceException** to continue to execute the for loop. When you try to get the element by any find_element method in a for loop.
from selenium.common import exceptions
and customize your code of for loop as:
for loop starts:
try:
driver.find_elements_by_id("data") //method to find element
//your code
except exceptions.StaleElementReferenceException:
pass

When you raise the StaleElementException that means that somthing changed in the site, but not in the list you have. So the trick is to refresh that list every time, inside the loop like this:
while True:
driver.implicitly_wait(4)
for d1 in driver.find_element_by_id('datatable-disclosures').find_element_by_tag_name('tbody').find_elements_by_tag_name('tr'):
tablewotags1.append(d1.text)
try:
driver.switch_to.default_content()
driver.find_element_by_xpath('//*[#id="datatable-disclosures_wrapper"]/div[2]/div[2]/div/ul/li[7]/a').click()
except NoSuchElementException:
print('Don\'t be so cryptic about error messages, they are good\n
...Script broke clicking next') #jk aside put some info there
break
Hope this help you, cheers.
Edit:
So I went to the said website, the layout is pretty straight forward, but the structure repeats itself like four times. So when you go about crawling the site like that something is bound to change.
So I’ve edited the code to only scrap one tbody tree. This tree comes from the first datatable-disclousure. And added some waits.

Wait until page is loaded with Selenium WebDriver for Python

I want to scrape all the data of a page implemented by a infinite scroll. The following python code works.
for i in range(100):
driver.execute_script("window.scrollTo(0, document.body.scrollHeight);")
time.sleep(5)
This means every time I scroll down to the bottom, I need to wait 5 seconds, which is generally enough for the page to finish loading the newly generated contents. But, this may not be time efficient. The page may finish loading the new contents within 5 seconds. How can I detect whether the page finished loading the new contents every time I scroll down? If I can detect this, I can scroll down again to see more contents once I know the page finished loading. This is more time efficient.

The webdriver will wait for a page to load by default via .get() method.
As you may be looking for some specific element as #user227215 said, you should use WebDriverWait to wait for an element located in your page:
from selenium import webdriver
from selenium.webdriver.support.ui import WebDriverWait
from selenium.webdriver.support import expected_conditions as EC
from selenium.webdriver.common.by import By
from selenium.common.exceptions import TimeoutException
browser = webdriver.Firefox()
browser.get("url")
delay = 3 # seconds
try:
myElem = WebDriverWait(browser, delay).until(EC.presence_of_element_located((By.ID, 'IdOfMyElement')))
print "Page is ready!"
except TimeoutException:
print "Loading took too much time!"
I have used it for checking alerts. You can use any other type methods to find the locator.
EDIT 1:
I should mention that the webdriver will wait for a page to load by default. It does not wait for loading inside frames or for ajax requests. It means when you use .get('url'), your browser will wait until the page is completely loaded and then go to the next command in the code. But when you are posting an ajax request, webdriver does not wait and it's your responsibility to wait an appropriate amount of time for the page or a part of page to load; so there is a module named expected_conditions.

Trying to pass find_element_by_id to the constructor for presence_of_element_located (as shown in the accepted answer) caused NoSuchElementException to be raised. I had to use the syntax in fragles' comment:
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
from selenium.webdriver.common.by import By
driver = webdriver.Firefox()
driver.get('url')
timeout = 5
try:
element_present = EC.presence_of_element_located((By.ID, 'element_id'))
WebDriverWait(driver, timeout).until(element_present)
except TimeoutException:
print "Timed out waiting for page to load"
This matches the example in the documentation. Here is a link to the documentation for By.

Find below 3 methods:
readyState
Checking page readyState (not reliable):
def page_has_loaded(self):
self.log.info("Checking if {} page is loaded.".format(self.driver.current_url))
page_state = self.driver.execute_script('return document.readyState;')
return page_state == 'complete'
The wait_for helper function is good, but unfortunately click_through_to_new_page is open to the race condition where we manage to execute the script in the old page, before the browser has started processing the click, and page_has_loaded just returns true straight away.
id
Comparing new page ids with the old one:
def page_has_loaded_id(self):
self.log.info("Checking if {} page is loaded.".format(self.driver.current_url))
try:
new_page = browser.find_element_by_tag_name('html')
return new_page.id != old_page.id
except NoSuchElementException:
return False
It's possible that comparing ids is not as effective as waiting for stale reference exceptions.
staleness_of
Using staleness_of method:
#contextlib.contextmanager
def wait_for_page_load(self, timeout=10):
self.log.debug("Waiting for page to load at {}.".format(self.driver.current_url))
old_page = self.find_element_by_tag_name('html')
yield
WebDriverWait(self, timeout).until(staleness_of(old_page))
For more details, check Harry's blog.

As mentioned in the answer from David Cullen, I've always seen recommendations to use a line like the following one:
element_present = EC.presence_of_element_located((By.ID, 'element_id'))
WebDriverWait(driver, timeout).until(element_present)
It was difficult for me to find somewhere all the possible locators that can be used with the By, so I thought it would be useful to provide the list here.
According to Web Scraping with Python by Ryan Mitchell:
ID
Used in the example; finds elements by their HTML id attribute
CLASS_NAME
Used to find elements by their HTML class attribute. Why is this
function CLASS_NAME not simply CLASS? Using the form object.CLASS
would create problems for Selenium's Java library, where .class is a
reserved method. In order to keep the Selenium syntax consistent
between different languages, CLASS_NAME was used instead.
CSS_SELECTOR
Finds elements by their class, id, or tag name, using the #idName,
.className, tagName convention.
LINK_TEXT
Finds HTML tags by the text they contain. For example, a link that
says "Next" can be selected using (By.LINK_TEXT, "Next").
PARTIAL_LINK_TEXT
Similar to LINK_TEXT, but matches on a partial string.
NAME
Finds HTML tags by their name attribute. This is handy for HTML forms.
TAG_NAME
Finds HTML tags by their tag name.
XPATH
Uses an XPath expression ... to select matching elements.

From selenium/webdriver/support/wait.py
driver = ...
from selenium.webdriver.support.wait import WebDriverWait
element = WebDriverWait(driver, 10).until(
lambda x: x.find_element_by_id("someId"))

On a side note, instead of scrolling down 100 times, you can check if there are no more modifications to the DOM (we are in the case of the bottom of the page being AJAX lazy-loaded)
def scrollDown(driver, value):
driver.execute_script("window.scrollBy(0,"+str(value)+")")
# Scroll down the page
def scrollDownAllTheWay(driver):
old_page = driver.page_source
while True:
logging.debug("Scrolling loop")
for i in range(2):
scrollDown(driver, 500)
time.sleep(2)
new_page = driver.page_source
if new_page != old_page:
old_page = new_page
else:
break
return True

Have you tried driver.implicitly_wait. It is like a setting for the driver, so you only call it once in the session and it basically tells the driver to wait the given amount of time until each command can be executed.
driver = webdriver.Chrome()
driver.implicitly_wait(10)
So if you set a wait time of 10 seconds it will execute the command as soon as possible, waiting 10 seconds before it gives up. I've used this in similar scroll-down scenarios so I don't see why it wouldn't work in your case. Hope this is helpful.
To be able to fix this answer, I have to add new text. Be sure to use a lower case 'w' in implicitly_wait.

Here I did it using a rather simple form:
from selenium import webdriver
browser = webdriver.Firefox()
browser.get("url")
searchTxt=''
while not searchTxt:
try:
searchTxt=browser.find_element_by_name('NAME OF ELEMENT')
searchTxt.send_keys("USERNAME")
except:continue

Solution for ajax pages that continuously load data. The previews methods stated do not work. What we can do instead is grab the page dom and hash it and compare old and new hash values together over a delta time.
import time
from selenium import webdriver
def page_has_loaded(driver, sleep_time = 2):
'''
Waits for page to completely load by comparing current page hash values.
'''
def get_page_hash(driver):
'''
Returns html dom hash
'''
# can find element by either 'html' tag or by the html 'root' id
dom = driver.find_element_by_tag_name('html').get_attribute('innerHTML')
# dom = driver.find_element_by_id('root').get_attribute('innerHTML')
dom_hash = hash(dom.encode('utf-8'))
return dom_hash
page_hash = 'empty'
page_hash_new = ''
# comparing old and new page DOM hash together to verify the page is fully loaded
while page_hash != page_hash_new:
page_hash = get_page_hash(driver)
time.sleep(sleep_time)
page_hash_new = get_page_hash(driver)
print('<page_has_loaded> - page not loaded')
print('<page_has_loaded> - page loaded: {}'.format(driver.current_url))

How about putting WebDriverWait in While loop and catching the exceptions.
from selenium import webdriver
from selenium.webdriver.support.ui import WebDriverWait
from selenium.webdriver.support import expected_conditions as EC
from selenium.common.exceptions import TimeoutException
browser = webdriver.Firefox()
browser.get("url")
delay = 3 # seconds
while True:
try:
WebDriverWait(browser, delay).until(EC.presence_of_element_located(browser.find_element_by_id('IdOfMyElement')))
print "Page is ready!"
break # it will break from the loop once the specific element will be present.
except TimeoutException:
print "Loading took too much time!-Try again"

You can do that very simple by this function:
def page_is_loading(driver):
while True:
x = driver.execute_script("return document.readyState")
if x == "complete":
return True
else:
yield False
and when you want do something after page loading complete,you can use:
Driver = webdriver.Firefox(options=Options, executable_path='geckodriver.exe')
Driver.get("https://www.google.com/")
while not page_is_loading(Driver):
continue
Driver.execute_script("alert('page is loaded')")

use this in code :
from selenium import webdriver
driver = webdriver.Firefox() # or Chrome()
driver.implicitly_wait(10) # seconds
driver.get("http://www.......")
or you can use this code if you are looking for a specific tag :
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
driver = webdriver.Firefox() #or Chrome()
driver.get("http://www.......")
try:
element = WebDriverWait(driver, 10).until(
EC.presence_of_element_located((By.ID, "tag_id"))
)
finally:
driver.quit()

Very good answers here. Quick example of wait for XPATH.
# wait for sizes to load - 2s timeout
try:
WebDriverWait(driver, 2).until(expected_conditions.presence_of_element_located(
(By.XPATH, "//div[#id='stockSizes']//a")))
except TimeoutException:
pass

I struggled a bit to get this working as that didn't worked for me as expected. anyone who is still struggling to get this working, may check this.
I want to wait for an element to be present on the webpage before proceeding with my manipulations.
we can use WebDriverWait(driver, 10, 1).until(), but the catch is until() expects a function which it can execute for a period of timeout provided(in our case its 10) for every 1 sec. so keeping it like below worked for me.
element_found = wait_for_element.until(lambda x: x.find_element_by_class_name("MY_ELEMENT_CLASS_NAME").is_displayed())
here is what until() do behind the scene
def until(self, method, message=''):
"""Calls the method provided with the driver as an argument until the \
return value is not False."""
screen = None
stacktrace = None
end_time = time.time() + self._timeout
while True:
try:
value = method(self._driver)
if value:
return value
except self._ignored_exceptions as exc:
screen = getattr(exc, 'screen', None)
stacktrace = getattr(exc, 'stacktrace', None)
time.sleep(self._poll)
if time.time() > end_time:
break
raise TimeoutException(message, screen, stacktrace)

If you are trying to scroll and find all items on a page. You can consider using the following. This is a combination of a few methods mentioned by others here. And it did the job for me:
while True:
try:
driver.execute_script("window.scrollTo(0, document.body.scrollHeight);")
driver.implicitly_wait(30)
time.sleep(4)
elem1 = WebDriverWait(driver, 30).until(EC.presence_of_all_elements_located((By.CSS_SELECTOR, "element-name")))
len_elem_1 = len(elem1)
print(f"A list Length {len_elem_1}")
driver.execute_script("window.scrollTo(0, document.body.scrollHeight);")
driver.implicitly_wait(30)
time.sleep(4)
elem2 = WebDriverWait(driver, 30).until(EC.presence_of_all_elements_located((By.CSS_SELECTOR, "element-name")))
len_elem_2 = len(elem2)
print(f"B list Length {len_elem_2}")
if len_elem_1 == len_elem_2:
print(f"final length = {len_elem_1}")
break
except TimeoutException:
print("Loading took too much time!")

selenium can't detect when the page is fully loaded or not, but javascript can. I suggest you try this.
from selenium.webdriver.support.ui import WebDriverWait
WebDriverWait(driver, 100).until(lambda driver: driver.execute_script('return document.readyState') == 'complete')
this will execute javascript code instead of using python, because javascript can detect when page is fully loaded, it will show 'complete'. This code means in 100 seconds, keep tryingn document.readyState until complete shows.

nono = driver.current_url
driver.find_element(By.XPATH,"//button[#value='Send']").click()
while driver.current_url == nono:
pass
print("page loaded.")