In this tutorial, we will look at how to resolve the error “bs4.FeatureNotFound: Couldn’t find a tree builder with the features you requested: lxml. Do you need to install a parser library?” in Python. In Pyton, ‘lxml’ is a versatile library which is widely used for tasks like web scraping, XML data processing and document transformation. This error generally occurs when you try to use the lxml library in your code without installing it. We will learn about how to fix the error in the upcoming section.
What is lxml ?
The ‘lxml’ is a popular Python library which is easy to use interface for processing XML and HTML documents. It is widely used for parsing and manipulating XML and HTML data in Python applications. It is based on ‘libxml2’ and libslt libraries, which are written in C. Some of the key usage of lxml package are mentioned below.
- Parse and manipulate XML and HTML documents
- Provides ElementTree like API to search, modify and create XML elements.
- Supports XPath and CSS Selectors to search for elements using complex patterns.
- Supports HTML document parsing making it useful for web scraping.
How to reproduce the error?
To reproduce the error, execute your Python code where you must be using lxml library in it. You will see the same error as shown below.
> python .\web_scrap.py Traceback (most recent call last): File "D:\python_projects\webScraping\web_scrap.py", line 8, in <module> result = BeautifulSoup(response.text, 'lxml') File "C:\Users\linuxnasa\.virtualenvs\webScraping-K00nvfpM\lib\site-packages\bs4\__init__.py", line 250, in __init__ raise FeatureNotFound( bs4.FeatureNotFound: Couldn't find a tree builder with the features you requested: lxml. Do you need to install a parser library?
How to Install lxml package?
To install the lxml library, execute below command. This will install the library in your current working project.
> pipenv install lxml Installing lxml... Adding lxml to Pipfile's [packages]... Installation Succeeded Pipfile.lock (3ccde6) out of date, updating to (8326fd)... Locking [packages] dependencies... Locking... Resolving dependencies... Success! Locking [dev-packages] dependencies... Updated Pipfile.lock (8326fd)! Installing dependencies from Pipfile.lock (8326fd)...
How to Unintsall lxml package?
To uninstall the ‘lxml’ package from your current working project, use the below command. This will uninstall the library along with all it’s dependencies.
> pipenv uninstall lxml Uninstalling lxml... Found existing installation: lxml 4.9.3 Uninstalling lxml-4.9.3: Successfully uninstalled lxml-4.9.3 Removing lxml from Pipfile... Locking [packages] dependencies... Locking...Building requirements... Resolving dependencies... Success! Locking [dev-packages] dependencies... Updated Pipfile.lock (3ccde6)!
We have successfully resolved the lxml library error. lxml release history reference – pypi.org