Selenium Python Tutorial

Selenium Python Tutorial

Selenium is a powerful tool for automating web applications. It can be used to perform a wide range of tasks, including:

• Testing web applications
• Scraping data from web pages
• Creating bots to interact with web applications

Selenium is a cross-browser testing framework that can be used to automate tests on any browser that supports WebDriver. WebDriver is a standard interface that allows programmers to control the browser using code.

Python is a popular programming language that is well-suited for web automation. It is easy to learn and has a large community of users.

This tutorial will teach you how to use Selenium to automate web applications using Python.

Prerequisites

• Python 3
• Selenium WebDriver
• A web browser (e.g., Chrome, Firefox, Edge)

Installation

To install Selenium WebDriver, you can use the following command:

Python

pip install selenium

 

Selenium Python Tutorial Topics

This tutorial will cover the following topics:

• Introduction to Selenium and Python
• Installing Selenium and Python
• Creating a Selenium script
• Navigating to a web page
• Finding elements on a web page
• Interacting with elements on a web page
• Closing the browser
• Locator strategies
• Webdriver commands
• Waiting for elements
• Handling alerts
• Working with frames
• Handling forms
• Taking screenshots
• Running tests in parallel

 

Creating a Selenium Script

To create a Selenium script, you will need to import the webdriver module and create an instance of the WebDriver class.

Python

from selenium import webdriver

driver = webdriver.Chrome()

Once you have created a WebDriver instance, you can use it to interact with the web browser.

Navigating to a Web Page

To navigate to a web page, you can use the get() method.

Python

driver.get("https://www.google.com")

Finding Elements

To find elements on a web page, you can use the find_element_by_*() methods. These methods take a locator strategy as an argument and return the first element that matches the locator.

There are a variety of locator strategies available, including:

• id
• name
• class_name
• tag_name
• css_selector
• xpath

For example, to find the element with the ID q, you would use the following code:

Python

element = driver.find_element_by_id("q")

Interacting with Elements

Once you have found an element, you can interact with it by calling its methods. For example, to enter text into an input field, you would use the send_keys() method.

Python

element.send_keys("Hello, world!")

You can also click on elements, submit forms, and perform other actions.

Closing the Browser

When you are finished with your script, you should close the browser by calling the quit() method on the WebDriver instance.

Python

driver.quit()

Example Script

The following is a simple example of a Selenium script in Python:

Python

from selenium import webdriver

driver = webdriver.Chrome()

driver.get("https://www.google.com")

element = driver.find_element_by_id("q")

element.send_keys("Hello, world!")

element.submit()

driver.quit()

Locator Strategies

Locator strategies are used to identify elements on a web page. Selenium provides a variety of locator strategies, including:

• id: This strategy locates elements by their unique identifier.
• name: This strategy locates elements by their name attribute.
• class_name: This strategy locates elements by their class attribute.
• tag_name: This strategy locates elements by their tag name.
• css_selector: This strategy locates elements using CSS selectors.
• xpath: This strategy locates elements using XPath expressions.

CSS selectors are a powerful way to locate elements on a web page. They are based on the Cascading Style Sheets (CSS) language, which is used to style web pages.

XPath expressions are another powerful way to locate elements on a web page. They are based on the XML Path Language (XPath), which is used to navigate XML documents.

Which locator strategy should you use?

The best locator strategy to use depends on the element you are trying to locate. If the element has a unique identifier, then you should use the id locator strategy. If the element does not have a unique identifier, then you can use the name, class_name, or tag_name locator strategy. If you need to locate an element using its CSS style or XPath expression, then you can use the css_selector or xpath locator strategy.

Examples

The following examples show how to use different locator strategies to locate elements on a web page:

Python

# Locate the element with the ID "my_element"
element = driver.find_element_by_id("my_element")

# Locate the element with the name "username"
element = driver.find_element_by_name("username")

# Locate the element with the class name "my_class"
element = driver.find_element_by_class_name("my_class")

# Locate the element with the tag name "input"
element = driver.find_element_by_tag_name("input")

# Locate the element using the CSS selector ".my_class"
element = driver.find_element_by_css_selector(".my_class")

# Locate the element using the XPath expression //input[@name='username']
element = driver.find_element_by_xpath("//input[@name='username']")

Webdriver Commands

Selenium provides a variety of WebDriver commands that can be used to interact with web pages. These commands can be used to navigate to web pages, find elements on web pages, interact with elements on web pages, and close the browser.

Some of the most common WebDriver commands include:

• get(): This command navigates to a web page.
• find_element_by_*(): These commands locate elements on a web page using different locator strategies.
• click(): This command clicks on an element.
• send_keys(): This command enters text into an element.
• submit(): This command submits a form.
• quit(): This command closes the browser.

Examples

The following examples show how to use different WebDriver commands to interact with web pages:

Python

# Navigate to the Google homepage
driver.get("https://www.google.com")

# Find the search bar element
search_bar_element = driver.find_element_by_id("q")

# Enter the search term "Hello, world!" into the search bar element
search_bar_element.send_keys("Hello, world!")

# Click on the search button element
search_button_element = driver.find_element_by_class_name("btnG")
search_button_element.click()

# Close the browser
driver.quit()

 

Waiting for Elements

When you are automating web applications, it is important to wait for elements to be present and visible before interacting with them. This is because web applications can take some time to load, and elements may not be available immediately.

There are two ways to wait for elements in Selenium Python:

• Implicit waits
• Explicit waits

Implicit waits tell Selenium to wait for a specified amount of time before throwing an exception if an element cannot be found.

Python

driver.implicitly_wait(10)

This will tell Selenium to wait for up to 10 seconds before throwing an exception if an element cannot be found.

Explicit waits allow you to wait for a specific condition to be met before interacting with an element. For example, you can wait for an element to be present, visible, clickable, or have a specific text.

Python

from selenium.webdriver.support.wait import WebDriverWait

wait = WebDriverWait(driver, 10)

element = wait.until(
    expected_conditions.presence_of_element_located((By.ID, "my_element"))
)

This will tell Selenium to wait for up to 10 seconds for the element with the ID my_element to be present before interacting with it.

Handling Alerts

Alerts are pop-up windows that are displayed by web applications. They are typically used to confirm or cancel an action.

To handle alerts in Selenium Python, you can use the alert property of the WebDriver instance.

Python

alert = driver.switch_to.alert

alert.accept()

This will accept the alert.

Python

alert = driver.switch_to.alert

alert.dismiss()

This will dismiss the alert.

Working with Frames

Frames are independent sections of a web page. They can be used to group related content together or to isolate content from the rest of the page.

To switch to a frame in Selenium Python, you can use the switch_to.frame() method.

Python

driver.switch_to.frame("my_frame")

This will switch to the frame with the ID my_frame.

To switch back to the default frame, you can use the switch_to.default_content() method.

Python

driver.switch_to.default_content()

Handling Forms

Forms are used to submit data to web applications.

To fill out a form in Selenium Python, you can use the find_element_by_*() methods to find the form elements and the send_keys() method to enter text into them.

Python

username_element = driver.find_element_by_id("username")
password_element = driver.find_element_by_id("password")

username_element.send_keys("my_username")
password_element.send_keys("my_password")

To submit the form, you can use the submit() method on the form element.

Python

form_element = driver.find_element_by_id("my_form")
form_element.submit()

Taking Screenshots

To take a screenshot in Selenium Python, you can use the save_screenshot() method.

Python

driver.save_screenshot("screenshot.png")

This will save a screenshot of the current browser window to the file screenshot.png.

Running Tests in Parallel

To run Selenium tests in parallel, you can use the pytest-xdist plugin.

To install the pytest-xdist plugin, you can use the following command:

Python

pip install pytest-xdist

To run your tests in parallel, you can use the following command:

pytest -n 2

This will run your tests in parallel using two worker processes.

 

Conclusion

Selenium is a powerful tool for automating web applications. It can be used to perform a wide range of tasks, including testing web applications, scraping data from web pages, and creating bots to interact with web applications.

Python is a popular programming language that is well-suited for web automation. It is easy to learn and has a large community of users.

This tutorial has taught you how to use Selenium to automate web applications using Python. You have learned how to create a Selenium script, navigate to a web page, find elements on a web page, interact with elements on a web page, and close the browser. You have also learned about locator strategies and Webdriver commands.

 

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