How to re-install lxml?

Question

Python version and Device used - Python 2,7.5 - Mac 10.7.5 - BeautifulSoup 4.2.1. I'm following the BeautifulSoup tutorial but when I try to parse a xml page using the lxml library I get the following error: ``` bs4.FeatureNotFound: Couldn't find a tree builder with the features you requested: lxml,xml. Do you need to install a parser library? ``` I am sure that I already installed lxml by all methods: easy_install, pip, port, etc. I tried to add a line to my code to see if lxml is installed or not: ``` import lxml ``` Then python can just successfully go through this code and display the previous error message again, occurring at the same line. So I am quite sure that lxml was installed, but not installed correctly. So I decided to uninstall lxml, and then re-install using a 'correct' method. But when I type in ``` easy_install -m lxml ``` I get the following error: ``` Searching for lxml Best match: lxml 3.2.1 Processing lxml-3.2.1-py2.7-macosx-10.6-intel.egg Using /Library/Framewor…

Accepted Answer

I am using BeautifulSoup 4.3.2 and OS X 10.6.8. I also have a problem with improperly installed `lxml`. Here are some things that I found out:

First of all, check this related question: Removed MacPorts, now Python is broken

Now, in order to check which builders for BeautifulSoup 4 are installed, try

```
>>> import bs4
>>> bs4.builder.builder_registry.builders
```

If you don't see your favorite builder, then it is not installed, and you will see an error as above ("Couldn't find a tree builder...").

Also, just because you can `import lxml`, doesn't mean that everything is perfect.

Try

```
>>> import lxml
>>> import lxml.etree
```

To understand what's going on, go to the `bs4` installation and open the egg (`tar -xvzf`). Notice the modules `bs4.builder`. Inside it you should see files such as `_lxml.py` and `_html5lib.py`. So you can also try

```
>>> import bs4.builder.htmlparser
>>> import bs4.builder._lxml
>>> import bs4.builder._html5lib
```

If there is a problem, you will see, why a parricular module cannot be loaded. You can notice how at the end of `builder/__init__.py` it loads all those modules and ignores whatever was not loaded:

```
# Builders are registered in reverse order of priority, so that custom
# builder registrations will take precedence. In general, we want lxml
# to take precedence over html5lib, because it's faster. And we only
# want to use HTMLParser as a last result.
from . import _htmlparser
register_treebuilders_from(_htmlparser)
try:
    from . import _html5lib
    register_treebuilders_from(_html5lib)
except ImportError:
    # They don't have html5lib installed.
    pass
try:
    from . import _lxml
    register_treebuilders_from(_lxml)
except ImportError:
    # They don't have lxml installed.
    pass
```

How to re-install lxml?

Solution

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