Selenium is a Python package that allows you to control web browsers through Python. In this tutorial (and the following tutorials), we will be connecting to Googles Chrome browser, Selenium does work with other browsers as well.
First you will need to download Selenium, you can use the following commands depending on your Python distribution
c:\> Pip install selenium
c:\> Conda install selenium
If you are on a work computer or dealing with a restrictive VPN, the offline install option may help you: Selenium_Install_Offline
Next you need to download the driver that let’s you manage Firefox through Python.
Start by determining what version of Firefox you have on your computer
Click the three horizontal lines in the upper right corner > Help >About Firefox
Search for geckodriver to download the file that matches your Firefox version. (note, this is something you will need to do every time Firefox is updated, so get used to it.)
Open up the zipfile you downloaded, you will find a file called geckodriver.exe
Put it somewhere you can find, put in the following code to let Python know where to find it.
from selenium import webdriver
opts = webdriver.FirefoxOptions()
dr = webdriver.Firefox('C:/Users/larsobe/Desktop/geckodriver.exe',chrome_options=opts)
Now to see if this works, use the following line, (you can try another website if you choose)
Note the message Firefoxis being controlled by automated test software.
This is follow up to how to connect to Chrome using Selenium. If you do not know how to get to a website on Chrome using Selenium, go here
To refresh. here is the code we used to open up a web page (in this case Wikipedia’s home page)
If you run this code, you should find yourself on the home page for Wikipedia
Okay, so now lets learn how to interact with page, the first thing I am going to do is to select the English language version of the page. There are a few ways go about this, but one of the easier approaches is to look at the HTML code that creates the page and to use xpaths or titles to find the object you are looking at.
Right click on the link for English and click inspect from the drop down.
If you get a body link first, you might need to right click and hit inspect again
To check if you have the right element, hover your mouse over it, and it will be highlighted on the webpage
Once you have the right element, right click on it, go to copy>Copy Xpath
Chose Xpath, not full Xpath, it makes for easier coding. You XPath should look something like this: //*[@id=”js-link-box-en”]/strong * When you go to try this, your XPath may look different. As websites are constantly updated, many of the Xpaths get updated as well. Go with the one you find when you Inspect the HTML code yourself
Now we are going to use selenium to “Find” the element we want. The code is dr.find_element_by_XPath(‘//*[@id=”js-link-box-en”]/strong’) *Note the use of single quote around the XPath, it is better to use them as many XPaths will contain double quotes
Once you have run that code, Selenium knows what element you are looking at, you can interact with it now. Let’s “click” the link
Note something i did in the code, I added a link= before my find element command. This assigned the element now to a variable. I can now use the “click()” method the variable inherited from the selenium.webdriver object to click on the English link
I could have just done this: dr.find_element_by_xpath(‘//*[@id=”js-link-box-en”]/strong’).click()
But by assigning the variable it is a) cleaner code and b) the link can be reused by my code later. Remember, it is a law of programming that you will always have to go back and fix something you haven’t seen in 6 months, so make the code as clean as possible to make future you less likely to develop a drinking problem due to having to fix poorly written code.
If you run the code above, you will move to the home English page
Lets try one more thing, lets typing a search into the search bar:
Right click > inspect the search bar, then right click>copy>copy xpath the selection in the HTML code
Now that you have the XPath, lets use the find_element_by_xpath code and a new command, send_keys() to input characters into the search box
Finally, right click on the magnifying glass>inspect>copy>copy Xpath and let us click on it to finish our search. (remember to hover over to make sure you have the right link)
Now you should find yourself on the Data Science page of Wikipedia
Now remember — the xpaths I have on this page will likely be out of date by the time you try this, so make sure to inspect the elements and get the correct XPaths for this work for you.
