Quick Start
Here’s an HTML document I’ll be using as an example throughout this document. It’s part of a story from Alice in Wonderland:
Running the “three sisters” document through Beautiful Soup gives us a BeautifulSoup
object, which represents the document as a nested data structure:
Here are some simple ways to navigate that data structure:
One common task is extracting all the URLs found within a page’s <a> tags:
Another common task is extracting all the text from a page:
Does this look like what you need? If so, read on.
Installing Beautiful Soup
If you’re using a recent version of Debian or Ubuntu Linux, you can install Beautiful Soup with the system package manager:
$ apt-get install python-bs4 (for Python 2)
$ apt-get install python3-bs4 (for Python 3)
Beautiful Soup 4 is published through PyPi, so if you can’t install it with the system packager, you can install it with easy_install
or pip
. The package name is beautifulsoup4
, and the same package works on Python 2 and Python 3. Make sure you use the right version of pip
or easy_install
for your Python version (these may be named pip3
and easy_install3
respectively if you’re using Python 3).
$ easy_install beautifulsoup4
$ pip install beautifulsoup4
(The BeautifulSoup
package is probably not what you want. That’s the previous major release, Beautiful Soup 3. Lots of software uses BS3, so it’s still available, but if you’re writing new code you should install beautifulsoup4
.)
If you don’t have easy_install
or pip
installed, you can download the Beautiful Soup 4 source tarball and install it with setup.py
.
$ python setup.py install
If all else fails, the license for Beautiful Soup allows you to package the entire library with your application. You can download the tarball, copy its bs4
directory into your application’s codebase, and use Beautiful Soup without installing it at all.
I use Python 2.7 and Python 3.2 to develop Beautiful Soup, but it should work with other recent versions.
Problems after installation
Beautiful Soup is packaged as Python 2 code. When you install it for use with Python 3, it’s automatically converted to Python 3 code. If you don’t install the package, the code won’t be converted. There have also been reports on Windows machines of the wrong version being installed.
If you get the ImportError
“No module named HTMLParser”, your problem is that you’re running the Python 2 version of the code under Python 3.
If you get the ImportError
“No module named html.parser”, your problem is that you’re running the Python 3 version of the code under Python 2.
In both cases, your best bet is to completely remove the Beautiful Soup installation from your system (including any directory created when you unzipped the tarball) and try the installation again.
If you get the SyntaxError
“Invalid syntax” on the line ROOT_TAG_NAME = u'[document]'
, you need to convert the Python 2 code to Python 3. You can do this either by installing the package:
$ python3 setup.py install
or by manually running Python’s 2to3
conversion script on the bs4
directory:
$ 2to3-3.2 -w bs4
Installing a parser
Beautiful Soup supports the HTML parser included in Python’s standard library, but it also supports a number of third-party Python parsers. One is the lxml parser. Depending on your setup, you might install lxml with one of these commands:
$ apt-get install python-lxml
$ easy_install lxml
$ pip install lxml
Another alternative is the pure-Python html5lib parser, which parses HTML the way a web browser does. Depending on your setup, you might install html5lib with one of these commands:
$ apt-get install python-html5lib
$ easy_install html5lib
$ pip install html5lib
This table summarizes the advantages and disadvantages of each parser library:
Parser | Typical usage | Advantages | Disadvantages |
Python’s html.parser |
|
|
|
lxml’s HTML parser |
|
|
|
lxml’s XML parser |
|
|
|
html5lib |
|
|
|
If you can, I recommend you install and use lxml for speed. If you’re using a very old version of Python – earlier than 2.7.3 or 3.2.2 – it’s essential that you install lxml or html5lib. Python’s built-in HTML parser is just not very good in those old versions.
Note that if a document is invalid, different parsers will generate different Beautiful Soup trees for it. See Differences between parsers for details.
Making the soup
To parse a document, pass it into the BeautifulSoup
constructor. You can pass in a string or an open filehandle:
First, the document is converted to Unicode, and HTML entities are converted to Unicode characters:
Beautiful Soup then parses the document using the best available parser. It will use an HTML parser unless you specifically tell it to use an XML parser. (See Parsing XML.)
Kinds of objects
Beautiful Soup transforms a complex HTML document into a complex tree of Python objects. But you’ll only ever have to deal with about four kinds of objects: Tag
, NavigableString
, BeautifulSoup
, and Comment
.
Tag
Tag
A Tag
object corresponds to an XML or HTML tag in the original document:
Tags have a lot of attributes and methods, and I’ll cover most of them in Navigating the tree and Searching the tree. For now, the most important features of a tag are its name and attributes.
Name
Every tag has a name, accessible as .name
:
If you change a tag’s name, the change will be reflected in any HTML markup generated by Beautiful Soup:
Attributes
A tag may have any number of attributes. The tag <b id="boldest">
has an attribute “id” whose value is “boldest”. You can access a tag’s attributes by treating the tag like a dictionary:
You can access that dictionary directly as .attrs
:
You can add, remove, and modify a tag’s attributes. Again, this is done by treating the tag as a dictionary:
Multi-valued attributes
HTML 4 defines a few attributes that can have multiple values. HTML 5 removes a couple of them, but defines a few more. The most common multi-valued attribute is class
(that is, a tag can have more than one CSS class). Others include rel
, rev
, accept-charset
, headers
, and accesskey
. Beautiful Soup presents the value(s) of a multi-valued attribute as a list:
If an attribute looks like it has more than one value, but it’s not a multi-valued attribute as defined by any version of the HTML standard, Beautiful Soup will leave the attribute alone:
When you turn a tag back into a string, multiple attribute values are consolidated:
You can disable this by passing multi_valued_attributes=None
as a keyword argument into the BeautifulSoup
constructor:
You can use `get_attribute_list
to get a value that’s always a list, whether or not it’s a multi-valued atribute:
If you parse a document as XML, there are no multi-valued attributes:
Again, you can configure this using the multi_valued_attributes
argument:
You probably won’t need to do this, but if you do, use the defaults as a guide. They implement the rules described in the HTML specification:
NavigableString
NavigableString
A string corresponds to a bit of text within a tag. Beautiful Soup uses the NavigableString
class to contain these bits of text:
A NavigableString
is just like a Python Unicode string, except that it also supports some of the features described in Navigating the tree and Searching the tree. You can convert a NavigableString
to a Unicode string with unicode()
:
You can’t edit a string in place, but you can replace one string with another, using replace_with():
NavigableString
supports most of the features described in Navigating the tree and Searching the tree, but not all of them. In particular, since a string can’t contain anything (the way a tag may contain a string or another tag), strings don’t support the .contents
or .string
attributes, or the find()
method.
If you want to use a NavigableString
outside of Beautiful Soup, you should call unicode()
on it to turn it into a normal Python Unicode string. If you don’t, your string will carry around a reference to the entire Beautiful Soup parse tree, even when you’re done using Beautiful Soup. This is a big waste of memory.
BeautifulSoup
BeautifulSoup
The BeautifulSoup
object represents the parsed document as a whole. For most purposes, you can treat it as a Tag object. This means it supports most of the methods described in Navigating the tree and Searching the tree.
You can also pass a BeautifulSoup
object into one of the methods defined in Modifying the tree, just as you would a Tag. This lets you do things like combine two parsed documents:
Since the BeautifulSoup
object doesn’t correspond to an actual HTML or XML tag, it has no name and no attributes. But sometimes it’s useful to look at its .name
, so it’s been given the special .name
“[document]”:
Comments and other special strings
Tag
, NavigableString
, and BeautifulSoup
cover almost everything you’ll see in an HTML or XML file, but there are a few leftover bits. The main one you’ll probably encounter is the comment:
The Comment
object is just a special type of NavigableString
:
But when it appears as part of an HTML document, a Comment
is displayed with special formatting:
Beautiful Soup also defines classes called Stylesheet
, Script
, and TemplateString
, for embedded CSS stylesheets (any strings found inside a <style>
tag), embedded Javascript (any strings found in a <script>
tag), and HTML templates (any strings inside a <template>
tag). These classes work exactly the same way as NavigableString
; their only purpose is to make it easier to pick out the main body of the page, by ignoring strings that represent something else. (These classes are new in Beautiful Soup 4.9.0, and the html5lib parser doesn’t use them.)
Beautiful Soup defines classes for anything else that might show up in an XML document: CData
, ProcessingInstruction
, Declaration
, and Doctype
. Like Comment
, these classes are subclasses of NavigableString
that add something extra to the string. Here’s an example that replaces the comment with a CDATA block:
Navigating the tree
Here’s the “Three sisters” HTML document again:
I’ll use this as an example to show you how to move from one part of a document to another.
Going down
Tags may contain strings and other tags. These elements are the tag’s children. Beautiful Soup provides a lot of different attributes for navigating and iterating over a tag’s children.
Note that Beautiful Soup strings don’t support any of these attributes, because a string can’t have children.
Navigating using tag names
The simplest way to navigate the parse tree is to say the name of the tag you want. If you want the <head> tag, just say soup.head
:
You can do use this trick again and again to zoom in on a certain part of the parse tree. This code gets the first <b> tag beneath the <body> tag:
Using a tag name as an attribute will give you only the first tag by that name:
If you need to get all the <a> tags, or anything more complicated than the first tag with a certain name, you’ll need to use one of the methods described in Searching the tree, such as find_all():
.contents
and .children
.contents
and .children
A tag’s children are available in a list called .contents
:
The BeautifulSoup
object itself has children. In this case, the <html> tag is the child of the BeautifulSoup
object.:
A string does not have .contents
, because it can’t contain anything:
Instead of getting them as a list, you can iterate over a tag’s children using the .children
generator:
.descendants
.descendants
The .contents
and .children
attributes only consider a tag’s direct children. For instance, the <head> tag has a single direct child–the <title> tag:
But the <title> tag itself has a child: the string “The Dormouse’s story”. There’s a sense in which that string is also a child of the <head> tag. The .descendants
attribute lets you iterate over all of a tag’s children, recursively: its direct children, the children of its direct children, and so on:
The <head> tag has only one child, but it has two descendants: the <title> tag and the <title> tag’s child. The BeautifulSoup
object only has one direct child (the <html> tag), but it has a whole lot of descendants:
.string
.string
If a tag has only one child, and that child is a NavigableString
, the child is made available as .string
:
If a tag’s only child is another tag, and that tag has a .string
, then the parent tag is considered to have the same .string
as its child:
If a tag contains more than one thing, then it’s not clear what .string
should refer to, so .string
is defined to be None
:
.strings
and stripped_strings
.strings
and stripped_strings
If there’s more than one thing inside a tag, you can still look at just the strings. Use the .strings
generator:
These strings tend to have a lot of extra whitespace, which you can remove by using the .stripped_strings
generator instead:
Here, strings consisting entirely of whitespace are ignored, and whitespace at the beginning and end of strings is removed.
Going up
Continuing the “family tree” analogy, every tag and every string has a parent: the tag that contains it.
.parent
.parent
You can access an element’s parent with the .parent
attribute. In the example “three sisters” document, the <head> tag is the parent of the <title> tag:
The title string itself has a parent: the <title> tag that contains it:
The parent of a top-level tag like <html> is the BeautifulSoup
object itself:
And the .parent
of a BeautifulSoup
object is defined as None:
.parents
.parents
You can iterate over all of an element’s parents with .parents
. This example uses .parents
to travel from an <a> tag buried deep within the document, to the very top of the document:
Going sideways
Consider a simple document like this:
The <b> tag and the <c> tag are at the same level: they’re both direct children of the same tag. We call them siblings. When a document is pretty-printed, siblings show up at the same indentation level. You can also use this relationship in the code you write.
.next_sibling
and .previous_sibling
.next_sibling
and .previous_sibling
You can use .next_sibling
and .previous_sibling
to navigate between page elements that are on the same level of the parse tree:
The <b> tag has a .next_sibling
, but no .previous_sibling
, because there’s nothing before the <b> tag on the same level of the tree. For the same reason, the <c> tag has a .previous_sibling
but no .next_sibling
:
The strings “text1” and “text2” are not siblings, because they don’t have the same parent:
In real documents, the .next_sibling
or .previous_sibling
of a tag will usually be a string containing whitespace. Going back to the “three sisters” document:
You might think that the .next_sibling
of the first <a> tag would be the second <a> tag. But actually, it’s a string: the comma and newline that separate the first <a> tag from the second:
The second <a> tag is actually the .next_sibling
of the comma:
.next_siblings
and .previous_siblings
.next_siblings
and .previous_siblings
You can iterate over a tag’s siblings with .next_siblings
or .previous_siblings
:
Going back and forth
Take a look at the beginning of the “three sisters” document:
An HTML parser takes this string of characters and turns it into a series of events: “open an <html> tag”, “open a <head> tag”, “open a <title> tag”, “add a string”, “close the <title> tag”, “open a <p> tag”, and so on. Beautiful Soup offers tools for reconstructing the initial parse of the document.
.next_element
and .previous_element
.next_element
and .previous_element
The .next_element
attribute of a string or tag points to whatever was parsed immediately afterwards. It might be the same as .next_sibling
, but it’s usually drastically different.
Here’s the final <a> tag in the “three sisters” document. Its .next_sibling
is a string: the conclusion of the sentence that was interrupted by the start of the <a> tag.:
But the .next_element
of that <a> tag, the thing that was parsed immediately after the <a> tag, is not the rest of that sentence: it’s the word “Tillie”:
That’s because in the original markup, the word “Tillie” appeared before that semicolon. The parser encountered an <a> tag, then the word “Tillie”, then the closing </a> tag, then the semicolon and rest of the sentence. The semicolon is on the same level as the <a> tag, but the word “Tillie” was encountered first.
The .previous_element
attribute is the exact opposite of .next_element
. It points to whatever element was parsed immediately before this one:
.next_elements
and .previous_elements
.next_elements
and .previous_elements
You should get the idea by now. You can use these iterators to move forward or backward in the document as it was parsed:
Searching the tree
Beautiful Soup defines a lot of methods for searching the parse tree, but they’re all very similar. I’m going to spend a lot of time explaining the two most popular methods: find()
and find_all()
. The other methods take almost exactly the same arguments, so I’ll just cover them briefly.
Once again, I’ll be using the “three sisters” document as an example:
By passing in a filter to an argument like find_all()
, you can zoom in on the parts of the document you’re interested in.
Kinds of filters
Before talking in detail about find_all()
and similar methods, I want to show examples of different filters you can pass into these methods. These filters show up again and again, throughout the search API. You can use them to filter based on a tag’s name, on its attributes, on the text of a string, or on some combination of these.
A string
The simplest filter is a string. Pass a string to a search method and Beautiful Soup will perform a match against that exact string. This code finds all the <b> tags in the document:
If you pass in a byte string, Beautiful Soup will assume the string is encoded as UTF-8. You can avoid this by passing in a Unicode string instead.
A regular expression
If you pass in a regular expression object, Beautiful Soup will filter against that regular expression using its search()
method. This code finds all the tags whose names start with the letter “b”; in this case, the <body> tag and the <b> tag:
This code finds all the tags whose names contain the letter ‘t’:
A list
If you pass in a list, Beautiful Soup will allow a string match against any item in that list. This code finds all the <a> tags and all the <b> tags:
True
True
The value True
matches everything it can. This code finds all the tags in the document, but none of the text strings:
A function
If none of the other matches work for you, define a function that takes an element as its only argument. The function should return True
if the argument matches, and False
otherwise.
Here’s a function that returns True
if a tag defines the “class” attribute but doesn’t define the “id” attribute:
Pass this function into find_all()
and you’ll pick up all the <p> tags:
This function only picks up the <p> tags. It doesn’t pick up the <a> tags, because those tags define both “class” and “id”. It doesn’t pick up tags like <html> and <title>, because those tags don’t define “class”.
If you pass in a function to filter on a specific attribute like href
, the argument passed into the function will be the attribute value, not the whole tag. Here’s a function that finds all a
tags whose href
attribute does not match a regular expression:
The function can be as complicated as you need it to be. Here’s a function that returns True
if a tag is surrounded by string objects:
Now we’re ready to look at the search methods in detail.
find_all()
find_all()
Signature: find_all(name, attrs, recursive, string, limit, **kwargs)
The find_all()
method looks through a tag’s descendants and retrieves all descendants that match your filters. I gave several examples in Kinds of filters, but here are a few more:
Some of these should look familiar, but others are new. What does it mean to pass in a value for string
, or id
? Why does find_all("p", "title")
find a <p> tag with the CSS class “title”? Let’s look at the arguments to find_all()
.
The name
argument
name
argumentPass in a value for name
and you’ll tell Beautiful Soup to only consider tags with certain names. Text strings will be ignored, as will tags whose names that don’t match.
This is the simplest usage:
Recall from Kinds of filters that the value to name
can be a string, a regular expression, a list, a function, or the value True.
The keyword arguments
Any argument that’s not recognized will be turned into a filter on one of a tag’s attributes. If you pass in a value for an argument called id
, Beautiful Soup will filter against each tag’s ‘id’ attribute:
If you pass in a value for href
, Beautiful Soup will filter against each tag’s ‘href’ attribute:
You can filter an attribute based on a string, a regular expression, a list, a function, or the value True.
This code finds all tags whose id
attribute has a value, regardless of what the value is:
You can filter multiple attributes at once by passing in more than one keyword argument:
Some attributes, like the data-* attributes in HTML 5, have names that can’t be used as the names of keyword arguments:
You can use these attributes in searches by putting them into a dictionary and passing the dictionary into find_all()
as the attrs
argument:
You can’t use a keyword argument to search for HTML’s ‘name’ element, because Beautiful Soup uses the name
argument to contain the name of the tag itself. Instead, you can give a value to ‘name’ in the attrs
argument:
Searching by CSS class
It’s very useful to search for a tag that has a certain CSS class, but the name of the CSS attribute, “class”, is a reserved word in Python. Using class
as a keyword argument will give you a syntax error. As of Beautiful Soup 4.1.2, you can search by CSS class using the keyword argument class_
:
As with any keyword argument, you can pass class_
a string, a regular expression, a function, or True
:
Remember that a single tag can have multiple values for its “class” attribute. When you search for a tag that matches a certain CSS class, you’re matching against any of its CSS classes:
You can also search for the exact string value of the class
attribute:
But searching for variants of the string value won’t work:
If you want to search for tags that match two or more CSS classes, you should use a CSS selector:
In older versions of Beautiful Soup, which don’t have the class_
shortcut, you can use the attrs
trick mentioned above. Create a dictionary whose value for “class” is the string (or regular expression, or whatever) you want to search for:
The string
argument
string
argumentWith string
you can search for strings instead of tags. As with name
and the keyword arguments, you can pass in a string, a regular expression, a list, a function, or the value True. Here are some examples:
Although string
is for finding strings, you can combine it with arguments that find tags: Beautiful Soup will find all tags whose .string
matches your value for string
. This code finds the <a> tags whose .string
is “Elsie”:
The string
argument is new in Beautiful Soup 4.4.0. In earlier versions it was called text
:
The limit
argument
limit
argumentfind_all()
returns all the tags and strings that match your filters. This can take a while if the document is large. If you don’t need all the results, you can pass in a number for limit
. This works just like the LIMIT keyword in SQL. It tells Beautiful Soup to stop gathering results after it’s found a certain number.
There are three links in the “three sisters” document, but this code only finds the first two:
The recursive
argument
recursive
argumentIf you call mytag.find_all()
, Beautiful Soup will examine all the descendants of mytag
: its children, its children’s children, and so on. If you only want Beautiful Soup to consider direct children, you can pass in recursive=False
. See the difference here:
Here’s that part of the document:
The <title> tag is beneath the <html> tag, but it’s not directly beneath the <html> tag: the <head> tag is in the way. Beautiful Soup finds the <title> tag when it’s allowed to look at all descendants of the <html> tag, but when recursive=False
restricts it to the <html> tag’s immediate children, it finds nothing.
Beautiful Soup offers a lot of tree-searching methods (covered below), and they mostly take the same arguments as find_all()
: name
, attrs
, string
, limit
, and the keyword arguments. But the recursive
argument is different: find_all()
and find()
are the only methods that support it. Passing recursive=False
into a method like find_parents()
wouldn’t be very useful.
Calling a tag is like calling find_all()
find_all()
Because find_all()
is the most popular method in the Beautiful Soup search API, you can use a shortcut for it. If you treat the BeautifulSoup
object or a Tag
object as though it were a function, then it’s the same as calling find_all()
on that object. These two lines of code are equivalent:
These two lines are also equivalent:
find()
find()
Signature: find(name, attrs, recursive, string, **kwargs)
The find_all()
method scans the entire document looking for results, but sometimes you only want to find one result. If you know a document only has one <body> tag, it’s a waste of time to scan the entire document looking for more. Rather than passing in limit=1
every time you call find_all
, you can use the find()
method. These two lines of code are nearly equivalent:
The only difference is that find_all()
returns a list containing the single result, and find()
just returns the result.
If find_all()
can’t find anything, it returns an empty list. If find()
can’t find anything, it returns None
:
Remember the soup.head.title
trick from Navigating using tag names? That trick works by repeatedly calling find()
:
find_parents()
and find_parent()
find_parents()
and find_parent()
Signature: find_parents(name, attrs, string, limit, **kwargs)
Signature: find_parent(name, attrs, string, **kwargs)
I spent a lot of time above covering find_all()
and find()
. The Beautiful Soup API defines ten other methods for searching the tree, but don’t be afraid. Five of these methods are basically the same as find_all()
, and the other five are basically the same as find()
. The only differences are in what parts of the tree they search.
First let’s consider find_parents()
and find_parent()
. Remember that find_all()
and find()
work their way down the tree, looking at tag’s descendants. These methods do the opposite: they work their way up the tree, looking at a tag’s (or a string’s) parents. Let’s try them out, starting from a string buried deep in the “three daughters” document:
One of the three <a> tags is the direct parent of the string in question, so our search finds it. One of the three <p> tags is an indirect parent of the string, and our search finds that as well. There’s a <p> tag with the CSS class “title” somewhere in the document, but it’s not one of this string’s parents, so we can’t find it with find_parents()
.
You may have made the connection between find_parent()
and find_parents()
, and the .parent and .parents attributes mentioned earlier. The connection is very strong. These search methods actually use .parents
to iterate over all the parents, and check each one against the provided filter to see if it matches.
find_next_siblings()
and find_next_sibling()
find_next_siblings()
and find_next_sibling()
Signature: find_next_siblings(name, attrs, string, limit, **kwargs)
Signature: find_next_sibling(name, attrs, string, **kwargs)
These methods use .next_siblings to iterate over the rest of an element’s siblings in the tree. The find_next_siblings()
method returns all the siblings that match, and find_next_sibling()
only returns the first one:
find_previous_siblings()
and find_previous_sibling()
find_previous_siblings()
and find_previous_sibling()
Signature: find_previous_siblings(name, attrs, string, limit, **kwargs)
Signature: find_previous_sibling(name, attrs, string, **kwargs)
These methods use .previous_siblings to iterate over an element’s siblings that precede it in the tree. The find_previous_siblings()
method returns all the siblings that match, and find_previous_sibling()
only returns the first one:
find_all_next()
and find_next()
find_all_next()
and find_next()
Signature: find_all_next(name, attrs, string, limit, **kwargs)
Signature: find_next(name, attrs, string, **kwargs)
These methods use .next_elements to iterate over whatever tags and strings that come after it in the document. The find_all_next()
method returns all matches, and find_next()
only returns the first match:
In the first example, the string “Elsie” showed up, even though it was contained within the <a> tag we started from. In the second example, the last <p> tag in the document showed up, even though it’s not in the same part of the tree as the <a> tag we started from. For these methods, all that matters is that an element match the filter, and show up later in the document than the starting element.
find_all_previous()
and find_previous()
find_all_previous()
and find_previous()
Signature: find_all_previous(name, attrs, string, limit, **kwargs)
Signature: find_previous(name, attrs, string, **kwargs)
These methods use .previous_elements to iterate over the tags and strings that came before it in the document. The find_all_previous()
method returns all matches, and find_previous()
only returns the first match:
The call to find_all_previous("p")
found the first paragraph in the document (the one with class=”title”), but it also finds the second paragraph, the <p> tag that contains the <a> tag we started with. This shouldn’t be too surprising: we’re looking at all the tags that show up earlier in the document than the one we started with. A <p> tag that contains an <a> tag must have shown up before the <a> tag it contains.
CSS selectors
BeautifulSoup
has a .select()
method which uses the SoupSieve package to run a CSS selector against a parsed document and return all the matching elements. Tag
has a similar method which runs a CSS selector against the contents of a single tag.
(The SoupSieve integration was added in Beautiful Soup 4.7.0. Earlier versions also have the .select()
method, but only the most commonly-used CSS selectors are supported. If you installed Beautiful Soup through pip
, SoupSieve was installed at the same time, so you don’t have to do anything extra.)
The SoupSieve documentation lists all the currently supported CSS selectors, but here are some of the basics:
You can find tags:
Find tags beneath other tags:
Find tags directly beneath other tags:
Find the siblings of tags:
Find tags by CSS class:
Find tags by ID:
Find tags that match any selector from a list of selectors:
Test for the existence of an attribute:
Find tags by attribute value:
There’s also a method called select_one()
, which finds only the first tag that matches a selector:
If you’ve parsed XML that defines namespaces, you can use them in CSS selectors.:
When handling a CSS selector that uses namespaces, Beautiful Soup uses the namespace abbreviations it found when parsing the document. You can override this by passing in your own dictionary of abbreviations:
All this CSS selector stuff is a convenience for people who already know the CSS selector syntax. You can do all of this with the Beautiful Soup API. And if CSS selectors are all you need, you should parse the document with lxml: it’s a lot faster. But this lets you combine CSS selectors with the Beautiful Soup API.
Modifying the tree
Beautiful Soup’s main strength is in searching the parse tree, but you can also modify the tree and write your changes as a new HTML or XML document.
Changing tag names and attributes
I covered this earlier, in Attributes, but it bears repeating. You can rename a tag, change the values of its attributes, add new attributes, and delete attributes:
Modifying .string
.string
If you set a tag’s .string
attribute to a new string, the tag’s contents are replaced with that string:
Be careful: if the tag contained other tags, they and all their contents will be destroyed.
append()
append()
You can add to a tag’s contents with Tag.append()
. It works just like calling .append()
on a Python list:
extend()
extend()
Starting in Beautiful Soup 4.7.0, Tag
also supports a method called .extend()
, which works just like calling .extend()
on a Python list:
NavigableString()
and .new_tag()
NavigableString()
and .new_tag()
If you need to add a string to a document, no problem–you can pass a Python string in to append()
, or you can call the NavigableString
constructor:
If you want to create a comment or some other subclass of NavigableString
, just call the constructor:
(This is a new feature in Beautiful Soup 4.4.0.)
What if you need to create a whole new tag? The best solution is to call the factory method BeautifulSoup.new_tag()
:
Only the first argument, the tag name, is required.
insert()
insert()
Tag.insert()
is just like Tag.append()
, except the new element doesn’t necessarily go at the end of its parent’s .contents
. It’ll be inserted at whatever numeric position you say. It works just like .insert()
on a Python list:
insert_before()
and insert_after()
insert_before()
and insert_after()
The insert_before()
method inserts tags or strings immediately before something else in the parse tree:
The insert_after()
method inserts tags or strings immediately following something else in the parse tree:
clear()
clear()
Tag.clear()
removes the contents of a tag:
extract()
extract()
PageElement.extract()
removes a tag or string from the tree. It returns the tag or string that was extracted:
At this point you effectively have two parse trees: one rooted at the BeautifulSoup
object you used to parse the document, and one rooted at the tag that was extracted. You can go on to call extract
on a child of the element you extracted:
decompose()
decompose()
Tag.decompose()
removes a tag from the tree, then completely destroys it and its contents:
The behavior of a decomposed Tag
or NavigableString
is not defined and you should not use it for anything. If you’re not sure whether something has been decomposed, you can check its .decomposed
property (new in Beautiful Soup 4.9.0):
replace_with()
replace_with()
PageElement.replace_with()
removes a tag or string from the tree, and replaces it with the tag or string of your choice:
replace_with()
returns the tag or string that was replaced, so that you can examine it or add it back to another part of the tree.
wrap()
wrap()
PageElement.wrap()
wraps an element in the tag you specify. It returns the new wrapper:
This method is new in Beautiful Soup 4.0.5.
unwrap()
unwrap()
Tag.unwrap()
is the opposite of wrap()
. It replaces a tag with whatever’s inside that tag. It’s good for stripping out markup:
Like replace_with()
, unwrap()
returns the tag that was replaced.
smooth()
smooth()
After calling a bunch of methods that modify the parse tree, you may end up with two or more NavigableString
objects next to each other. Beautiful Soup doesn’t have any problems with this, but since it can’t happen in a freshly parsed document, you might not expect behavior like the following:
You can call Tag.smooth()
to clean up the parse tree by consolidating adjacent strings:
The smooth()
method is new in Beautiful Soup 4.8.0.
Output
Pretty-printing
The prettify()
method will turn a Beautiful Soup parse tree into a nicely formatted Unicode string, with a separate line for each tag and each string:
You can call prettify()
on the top-level BeautifulSoup
object, or on any of its Tag
objects:
Since it adds whitespace (in the form of newlines), prettify()
changes the meaning of an HTML document and should not be used to reformat one. The goal of prettify()
is to help you visually understand the structure of the documents you work with.
Non-pretty printing
If you just want a string, with no fancy formatting, you can call unicode()
or str()
on a BeautifulSoup
object, or a Tag
within it:
The str()
function returns a string encoded in UTF-8. See Encodings for other options.
You can also call encode()
to get a bytestring, and decode()
to get Unicode.
Output formatters
If you give Beautiful Soup a document that contains HTML entities like “&lquot;”, they’ll be converted to Unicode characters:
If you then convert the document to a string, the Unicode characters will be encoded as UTF-8. You won’t get the HTML entities back:
By default, the only characters that are escaped upon output are bare ampersands and angle brackets. These get turned into “&”, “<”, and “>”, so that Beautiful Soup doesn’t inadvertently generate invalid HTML or XML:
You can change this behavior by providing a value for the formatter
argument to prettify()
, encode()
, or decode()
. Beautiful Soup recognizes five possible values for formatter
.
The default is formatter="minimal"
. Strings will only be processed enough to ensure that Beautiful Soup generates valid HTML/XML:
If you pass in formatter="html"
, Beautiful Soup will convert Unicode characters to HTML entities whenever possible:
If you pass in formatter="html5"
, it’s the same as formatter="html"
, but Beautiful Soup will omit the closing slash in HTML void tags like “br”:
If you pass in formatter=None
, Beautiful Soup will not modify strings at all on output. This is the fastest option, but it may lead to Beautiful Soup generating invalid HTML/XML, as in these examples:
If you need more sophisticated control over your output, you can use Beautiful Soup’s Formatter
class. Here’s a formatter that converts strings to uppercase, whether they occur in a text node or in an attribute value:
Subclassing HTMLFormatter
or XMLFormatter
will give you even more control over the output. For example, Beautiful Soup sorts the attributes in every tag by default:
To turn this off, you can subclass the Formatter.attributes()
method, which controls which attributes are output and in what order. This implementation also filters out the attribute called “m” whenever it appears:
One last caveat: if you create a CData
object, the text inside that object is always presented exactly as it appears, with no formatting. Beautiful Soup will call your entity substitution function, just in case you’ve written a custom function that counts all the strings in the document or something, but it will ignore the return value:
get_text()
get_text()
If you only want the human-readable text inside a document or tag, you can use the get_text()
method. It returns all the text in a document or beneath a tag, as a single Unicode string:
You can specify a string to be used to join the bits of text together:
You can tell Beautiful Soup to strip whitespace from the beginning and end of each bit of text:
But at that point you might want to use the .stripped_strings generator instead, and process the text yourself:
As of Beautiful Soup version 4.9.0, when lxml or html.parser are in use, the contents of <script>, <style>, and <template> tags are not considered to be ‘text’, since those tags are not part of the human-visible content of the page.
Specifying the parser to use
If you just need to parse some HTML, you can dump the markup into the BeautifulSoup
constructor, and it’ll probably be fine. Beautiful Soup will pick a parser for you and parse the data. But there are a few additional arguments you can pass in to the constructor to change which parser is used.
The first argument to the BeautifulSoup
constructor is a string or an open filehandle–the markup you want parsed. The second argument is how you’d like the markup parsed.
If you don’t specify anything, you’ll get the best HTML parser that’s installed. Beautiful Soup ranks lxml’s parser as being the best, then html5lib’s, then Python’s built-in parser. You can override this by specifying one of the following:
What type of markup you want to parse. Currently supported are “html”, “xml”, and “html5”.
The name of the parser library you want to use. Currently supported options are “lxml”, “html5lib”, and “html.parser” (Python’s built-in HTML parser).
The section Installing a parser contrasts the supported parsers.
If you don’t have an appropriate parser installed, Beautiful Soup will ignore your request and pick a different parser. Right now, the only supported XML parser is lxml. If you don’t have lxml installed, asking for an XML parser won’t give you one, and asking for “lxml” won’t work either.
Differences between parsers
Beautiful Soup presents the same interface to a number of different parsers, but each parser is different. Different parsers will create different parse trees from the same document. The biggest differences are between the HTML parsers and the XML parsers. Here’s a short document, parsed as HTML using the parser that comes with Python:
Since a standalone <b/> tag is not valid HTML, html.parser turns it into a <b></b> tag pair.
Here’s the same document parsed as XML (running this requires that you have lxml installed). Note that the standalone <b/> tag is left alone, and that the document is given an XML declaration instead of being put into an <html> tag.:
There are also differences between HTML parsers. If you give Beautiful Soup a perfectly-formed HTML document, these differences won’t matter. One parser will be faster than another, but they’ll all give you a data structure that looks exactly like the original HTML document.
But if the document is not perfectly-formed, different parsers will give different results. Here’s a short, invalid document parsed using lxml’s HTML parser. Note that the <a> tag gets wrapped in <body> and <html> tags, and the dangling </p> tag is simply ignored:
Here’s the same document parsed using html5lib:
Instead of ignoring the dangling </p> tag, html5lib pairs it with an opening <p> tag. html5lib also adds an empty <head> tag; lxml didn’t bother.
Here’s the same document parsed with Python’s built-in HTML parser:
Like html5lib, this parser ignores the closing </p> tag. Unlike html5lib or lxml, this parser makes no attempt to create a well-formed HTML document by adding <html> or <body> tags.
Since the document “<a></p>” is invalid, none of these techniques is the ‘correct’ way to handle it. The html5lib parser uses techniques that are part of the HTML5 standard, so it has the best claim on being the ‘correct’ way, but all three techniques are legitimate.
Differences between parsers can affect your script. If you’re planning on distributing your script to other people, or running it on multiple machines, you should specify a parser in the BeautifulSoup
constructor. That will reduce the chances that your users parse a document differently from the way you parse it.
Encodings
Any HTML or XML document is written in a specific encoding like ASCII or UTF-8. But when you load that document into Beautiful Soup, you’ll discover it’s been converted to Unicode:
It’s not magic. (That sure would be nice.) Beautiful Soup uses a sub-library called Unicode, Dammit to detect a document’s encoding and convert it to Unicode. The autodetected encoding is available as the .original_encoding
attribute of the BeautifulSoup
object:
Unicode, Dammit guesses correctly most of the time, but sometimes it makes mistakes. Sometimes it guesses correctly, but only after a byte-by-byte search of the document that takes a very long time. If you happen to know a document’s encoding ahead of time, you can avoid mistakes and delays by passing it to the BeautifulSoup
constructor as from_encoding
.
Here’s a document written in ISO-8859-8. The document is so short that Unicode, Dammit can’t get a lock on it, and misidentifies it as ISO-8859-7:
We can fix this by passing in the correct from_encoding
:
If you don’t know what the correct encoding is, but you know that Unicode, Dammit is guessing wrong, you can pass the wrong guesses in as exclude_encodings
:
Windows-1255 isn’t 100% correct, but that encoding is a compatible superset of ISO-8859-8, so it’s close enough. (exclude_encodings
is a new feature in Beautiful Soup 4.4.0.)
In rare cases (usually when a UTF-8 document contains text written in a completely different encoding), the only way to get Unicode may be to replace some characters with the special Unicode character “REPLACEMENT CHARACTER” (U+FFFD, �). If Unicode, Dammit needs to do this, it will set the .contains_replacement_characters
attribute to True
on the UnicodeDammit
or BeautifulSoup
object. This lets you know that the Unicode representation is not an exact representation of the original–some data was lost. If a document contains �, but .contains_replacement_characters
is False
, you’ll know that the � was there originally (as it is in this paragraph) and doesn’t stand in for missing data.
Output encoding
When you write out a document from Beautiful Soup, you get a UTF-8 document, even if the document wasn’t in UTF-8 to begin with. Here’s a document written in the Latin-1 encoding:
Note that the <meta> tag has been rewritten to reflect the fact that the document is now in UTF-8.
If you don’t want UTF-8, you can pass an encoding into prettify()
:
You can also call encode() on the BeautifulSoup
object, or any element in the soup, just as if it were a Python string:
Any characters that can’t be represented in your chosen encoding will be converted into numeric XML entity references. Here’s a document that includes the Unicode character SNOWMAN:
The SNOWMAN character can be part of a UTF-8 document (it looks like ☃), but there’s no representation for that character in ISO-Latin-1 or ASCII, so it’s converted into “☃” for those encodings:
Unicode, Dammit
You can use Unicode, Dammit without using Beautiful Soup. It’s useful whenever you have data in an unknown encoding and you just want it to become Unicode:
Unicode, Dammit’s guesses will get a lot more accurate if you install the chardet
or cchardet
Python libraries. The more data you give Unicode, Dammit, the more accurately it will guess. If you have your own suspicions as to what the encoding might be, you can pass them in as a list:
Unicode, Dammit has two special features that Beautiful Soup doesn’t use.
Smart quotes
You can use Unicode, Dammit to convert Microsoft smart quotes to HTML or XML entities:
You can also convert Microsoft smart quotes to ASCII quotes:
Hopefully you’ll find this feature useful, but Beautiful Soup doesn’t use it. Beautiful Soup prefers the default behavior, which is to convert Microsoft smart quotes to Unicode characters along with everything else:
Inconsistent encodings
Sometimes a document is mostly in UTF-8, but contains Windows-1252 characters such as (again) Microsoft smart quotes. This can happen when a website includes data from multiple sources. You can use UnicodeDammit.detwingle()
to turn such a document into pure UTF-8. Here’s a simple example:
This document is a mess. The snowmen are in UTF-8 and the quotes are in Windows-1252. You can display the snowmen or the quotes, but not both:
Decoding the document as UTF-8 raises a UnicodeDecodeError
, and decoding it as Windows-1252 gives you gibberish. Fortunately, UnicodeDammit.detwingle()
will convert the string to pure UTF-8, allowing you to decode it to Unicode and display the snowmen and quote marks simultaneously:
UnicodeDammit.detwingle()
only knows how to handle Windows-1252 embedded in UTF-8 (or vice versa, I suppose), but this is the most common case.
Note that you must know to call UnicodeDammit.detwingle()
on your data before passing it into BeautifulSoup
or the UnicodeDammit
constructor. Beautiful Soup assumes that a document has a single encoding, whatever it might be. If you pass it a document that contains both UTF-8 and Windows-1252, it’s likely to think the whole document is Windows-1252, and the document will come out looking like ☃☃☃“I like snowmen!”
.
UnicodeDammit.detwingle()
is new in Beautiful Soup 4.1.0.
Line numbers
The html.parser
and html5lib
parsers can keep track of where in the original document each Tag was found. You can access this information as Tag.sourceline
(line number) and Tag.sourcepos
(position of the start tag within a line):
Note that the two parsers mean slightly different things by sourceline
and sourcepos
. For html.parser, these numbers represent the position of the initial less-than sign. For html5lib, these numbers represent the position of the final greater-than sign:
You can shut off this feature by passing store_line_numbers=False` into the ``BeautifulSoup
constructor:
This feature is new in 4.8.1, and the parsers based on lxml don’t support it.
Comparing objects for equality
Beautiful Soup says that two NavigableString
or Tag
objects are equal when they represent the same HTML or XML markup. In this example, the two <b> tags are treated as equal, even though they live in different parts of the object tree, because they both look like “<b>pizza</b>”:
If you want to see whether two variables refer to exactly the same object, use is:
Copying Beautiful Soup objects
You can use copy.copy()
to create a copy of any Tag
or NavigableString
:
The copy is considered equal to the original, since it represents the same markup as the original, but it’s not the same object:
The only real difference is that the copy is completely detached from the original Beautiful Soup object tree, just as if extract()
had been called on it:
This is because two different Tag
objects can’t occupy the same space at the same time.
Advanced parser customization
Beautiful Soup offers a number of ways to customize how the parser treats incoming HTML and XML. This section covers the most commonly used customization techniques.
Parsing only part of a document
Let’s say you want to use Beautiful Soup look at a document’s <a> tags. It’s a waste of time and memory to parse the entire document and then go over it again looking for <a> tags. It would be much faster to ignore everything that wasn’t an <a> tag in the first place. The SoupStrainer
class allows you to choose which parts of an incoming document are parsed. You just create a SoupStrainer
and pass it in to the BeautifulSoup
constructor as the parse_only
argument.
(Note that this feature won’t work if you’re using the html5lib parser. If you use html5lib, the whole document will be parsed, no matter what. This is because html5lib constantly rearranges the parse tree as it works, and if some part of the document didn’t actually make it into the parse tree, it’ll crash. To avoid confusion, in the examples below I’ll be forcing Beautiful Soup to use Python’s built-in parser.)
SoupStrainer
SoupStrainer
The SoupStrainer
class takes the same arguments as a typical method from Searching the tree: name, attrs, string, and **kwargs. Here are three SoupStrainer
objects:
I’m going to bring back the “three sisters” document one more time, and we’ll see what the document looks like when it’s parsed with these three SoupStrainer
objects:
You can also pass a SoupStrainer
into any of the methods covered in Searching the tree. This probably isn’t terribly useful, but I thought I’d mention it:
Customizing multi-valued attributes
In an HTML document, an attribute like class
is given a list of values, and an attribute like id
is given a single value, because the HTML specification treats those attributes differently:
You can turn this off by passing in multi_valued_attributes=None
. Than all attributes will be given a single value:
You can customize this behavior quite a bit by passing in a dictionary for multi_valued_attributes
. If you need this, look at HTMLTreeBuilder.DEFAULT_CDATA_LIST_ATTRIBUTES
to see the configuration Beautiful Soup uses by default, which is based on the HTML specification.
(This is a new feature in Beautiful Soup 4.8.0.)
Handling duplicate attributes
When using the html.parser
parser, you can use the on_duplicate_attribute
constructor argument to customize what Beautiful Soup does when it encounters a tag that defines the same attribute more than once:
The default behavior is to use the last value found for the tag:
With on_duplicate_attribute='ignore'
you can tell Beautiful Soup to use the first value found and ignore the rest:
(lxml and html5lib always do it this way; their behavior can’t be configured from within Beautiful Soup.)
If you need more, you can pass in a function that’s called on each duplicate value:
(This is a new feature in Beautiful Soup 4.9.1.)
Instantiating custom subclasses
When a parser tells Beautiful Soup about a tag or a string, Beautiful Soup will instantiate a Tag
or NavigableString
object to contain that information. Instead of that default behavior, you can tell Beautiful Soup to instantiate subclasses of Tag
or NavigableString
, subclasses you define with custom behavior:
This can be useful when incorporating Beautiful Soup into a test framework.
(This is a new feature in Beautiful Soup 4.8.1.)
Troubleshooting
diagnose()
diagnose()
If you’re having trouble understanding what Beautiful Soup does to a document, pass the document into the diagnose()
function. (New in Beautiful Soup 4.2.0.) Beautiful Soup will print out a report showing you how different parsers handle the document, and tell you if you’re missing a parser that Beautiful Soup could be using:
Just looking at the output of diagnose() may show you how to solve the problem. Even if not, you can paste the output of diagnose()
when asking for help.
Errors when parsing a document
There are two different kinds of parse errors. There are crashes, where you feed a document to Beautiful Soup and it raises an exception, usually an HTMLParser.HTMLParseError
. And there is unexpected behavior, where a Beautiful Soup parse tree looks a lot different than the document used to create it.
Almost none of these problems turn out to be problems with Beautiful Soup. This is not because Beautiful Soup is an amazingly well-written piece of software. It’s because Beautiful Soup doesn’t include any parsing code. Instead, it relies on external parsers. If one parser isn’t working on a certain document, the best solution is to try a different parser. See Installing a parser for details and a parser comparison.
The most common parse errors are HTMLParser.HTMLParseError: malformed start tag
and HTMLParser.HTMLParseError: bad end tag
. These are both generated by Python’s built-in HTML parser library, and the solution is to install lxml or html5lib.
The most common type of unexpected behavior is that you can’t find a tag that you know is in the document. You saw it going in, but find_all()
returns []
or find()
returns None
. This is another common problem with Python’s built-in HTML parser, which sometimes skips tags it doesn’t understand. Again, the best solution is to install lxml or html5lib.
Version mismatch problems
SyntaxError: Invalid syntax
(on the lineROOT_TAG_NAME = u'[document]'
): Caused by running the Python 2 version of Beautiful Soup under Python 3, without converting the code.ImportError: No module named HTMLParser
- Caused by running the Python 2 version of Beautiful Soup under Python 3.ImportError: No module named html.parser
- Caused by running the Python 3 version of Beautiful Soup under Python 2.ImportError: No module named BeautifulSoup
- Caused by running Beautiful Soup 3 code on a system that doesn’t have BS3 installed. Or, by writing Beautiful Soup 4 code without knowing that the package name has changed tobs4
.ImportError: No module named bs4
- Caused by running Beautiful Soup 4 code on a system that doesn’t have BS4 installed.
Parsing XML
By default, Beautiful Soup parses documents as HTML. To parse a document as XML, pass in “xml” as the second argument to the BeautifulSoup
constructor:
You’ll need to have lxml installed.
Other parser problems
If your script works on one computer but not another, or in one virtual environment but not another, or outside the virtual environment but not inside, it’s probably because the two environments have different parser libraries available. For example, you may have developed the script on a computer that has lxml installed, and then tried to run it on a computer that only has html5lib installed. See Differences between parsers for why this matters, and fix the problem by mentioning a specific parser library in the
BeautifulSoup
constructor.Because HTML tags and attributes are case-insensitive, all three HTML parsers convert tag and attribute names to lowercase. That is, the markup <TAG></TAG> is converted to <tag></tag>. If you want to preserve mixed-case or uppercase tags and attributes, you’ll need to parse the document as XML.
Miscellaneous
UnicodeEncodeError: 'charmap' codec can't encode character u'\xfoo' in position bar
(or just about any otherUnicodeEncodeError
) - This problem shows up in two main situations. First, when you try to print a Unicode character that your console doesn’t know how to display. (See this page on the Python wiki for help.) Second, when you’re writing to a file and you pass in a Unicode character that’s not supported by your default encoding. In this case, the simplest solution is to explicitly encode the Unicode string into UTF-8 withu.encode("utf8")
.KeyError: [attr]
- Caused by accessingtag['attr']
when the tag in question doesn’t define theattr
attribute. The most common errors areKeyError: 'href'
andKeyError: 'class'
. Usetag.get('attr')
if you’re not sureattr
is defined, just as you would with a Python dictionary.AttributeError: 'ResultSet' object has no attribute 'foo'
- This usually happens because you expectedfind_all()
to return a single tag or string. Butfind_all()
returns a _list_ of tags and strings–aResultSet
object. You need to iterate over the list and look at the.foo
of each one. Or, if you really only want one result, you need to usefind()
instead offind_all()
.AttributeError: 'NoneType' object has no attribute 'foo'
- This usually happens because you calledfind()
and then tried to access the .foo` attribute of the result. But in your case,find()
didn’t find anything, so it returnedNone
, instead of returning a tag or a string. You need to figure out why yourfind()
call isn’t returning anything.AttributeError: 'NavigableString' object has no attribute 'foo'
- This usually happens because you’re treating a string as though it were a tag. You may be iterating over a list, expecting that it contains nothing but tags, when it actually contains both tags and strings.
Improving Performance
Beautiful Soup will never be as fast as the parsers it sits on top of. If response time is critical, if you’re paying for computer time by the hour, or if there’s any other reason why computer time is more valuable than programmer time, you should forget about Beautiful Soup and work directly atop lxml.
That said, there are things you can do to speed up Beautiful Soup. If you’re not using lxml as the underlying parser, my advice is to start. Beautiful Soup parses documents significantly faster using lxml than using html.parser or html5lib.
You can speed up encoding detection significantly by installing the cchardet library.
Parsing only part of a document won’t save you much time parsing the document, but it can save a lot of memory, and it’ll make searching the document much faster.
Translating this documentation
New translations of the Beautiful Soup documentation are greatly appreciated. Translations should be licensed under the MIT license, just like Beautiful Soup and its English documentation are.
There are two ways of getting your translation into the main code base and onto the Beautiful Soup website:
Create a branch of the Beautiful Soup repository, add your translation, and propose a merge with the main branch, the same as you would do with a proposed change to the source code.
Send a message to the Beautiful Soup discussion group with a link to your translation, or attach your translation to the message.
Use the Chinese or Brazilian Portuguese translations as your model. In particular, please translate the source file doc/source/index.rst
, rather than the HTML version of the documentation. This makes it possible to publish the documentation in a variety of formats, not just HTML.
Beautiful Soup 3
Beautiful Soup 3 is the previous release series, and is no longer being actively developed. It’s currently packaged with all major Linux distributions:
$ apt-get install python-beautifulsoup
It’s also published through PyPi as BeautifulSoup
.:
$ easy_install BeautifulSoup
$ pip install BeautifulSoup
You can also download a tarball of Beautiful Soup 3.2.0.
If you ran easy_install beautifulsoup
or easy_install BeautifulSoup
, but your code doesn’t work, you installed Beautiful Soup 3 by mistake. You need to run easy_install beautifulsoup4
.
The documentation for Beautiful Soup 3 is archived online.
Porting code to BS4
Most code written against Beautiful Soup 3 will work against Beautiful Soup 4 with one simple change. All you should have to do is change the package name from BeautifulSoup
to bs4
. So this:
becomes this:
If you get the
ImportError
“No module named BeautifulSoup”, your problem is that you’re trying to run Beautiful Soup 3 code, but you only have Beautiful Soup 4 installed.If you get the
ImportError
“No module named bs4”, your problem is that you’re trying to run Beautiful Soup 4 code, but you only have Beautiful Soup 3 installed.
Although BS4 is mostly backwards-compatible with BS3, most of its methods have been deprecated and given new names for PEP 8 compliance. There are numerous other renames and changes, and a few of them break backwards compatibility.
Here’s what you’ll need to know to convert your BS3 code and habits to BS4:
You need a parser
Beautiful Soup 3 used Python’s SGMLParser
, a module that was deprecated and removed in Python 3.0. Beautiful Soup 4 uses html.parser
by default, but you can plug in lxml or html5lib and use that instead. See Installing a parser for a comparison.
Since html.parser
is not the same parser as SGMLParser
, you may find that Beautiful Soup 4 gives you a different parse tree than Beautiful Soup 3 for the same markup. If you swap out html.parser
for lxml or html5lib, you may find that the parse tree changes yet again. If this happens, you’ll need to update your scraping code to deal with the new tree.
Method names
renderContents
->encode_contents
replaceWith
->replace_with
replaceWithChildren
->unwrap
findAll
->find_all
findAllNext
->find_all_next
findAllPrevious
->find_all_previous
findNext
->find_next
findNextSibling
->find_next_sibling
findNextSiblings
->find_next_siblings
findParent
->find_parent
findParents
->find_parents
findPrevious
->find_previous
findPreviousSibling
->find_previous_sibling
findPreviousSiblings
->find_previous_siblings
getText
->get_text
nextSibling
->next_sibling
previousSibling
->previous_sibling
Some arguments to the Beautiful Soup constructor were renamed for the same reasons:
BeautifulSoup(parseOnlyThese=...)
->BeautifulSoup(parse_only=...)
BeautifulSoup(fromEncoding=...)
->BeautifulSoup(from_encoding=...)
I renamed one method for compatibility with Python 3:
Tag.has_key()
->Tag.has_attr()
I renamed one attribute to use more accurate terminology:
Tag.isSelfClosing
->Tag.is_empty_element
I renamed three attributes to avoid using words that have special meaning to Python. Unlike the others, these changes are not backwards compatible. If you used these attributes in BS3, your code will break on BS4 until you change them.
UnicodeDammit.unicode
->UnicodeDammit.unicode_markup
Tag.next
->Tag.next_element
Tag.previous
->Tag.previous_element
These methods are left over from the Beautiful Soup 2 API. They’ve been deprecated since 2006, and should not be used at all:
Tag.fetchNextSiblings
Tag.fetchPreviousSiblings
Tag.fetchPrevious
Tag.fetchPreviousSiblings
Tag.fetchParents
Tag.findChild
Tag.findChildren
Generators
I gave the generators PEP 8-compliant names, and transformed them into properties:
childGenerator()
->children
nextGenerator()
->next_elements
nextSiblingGenerator()
->next_siblings
previousGenerator()
->previous_elements
previousSiblingGenerator()
->previous_siblings
recursiveChildGenerator()
->descendants
parentGenerator()
->parents
So instead of this:
You can write this:
(But the old code will still work.)
Some of the generators used to yield None
after they were done, and then stop. That was a bug. Now the generators just stop.
There are two new generators, .strings and .stripped_strings. .strings
yields NavigableString objects, and .stripped_strings
yields Python strings that have had whitespace stripped.
XML
There is no longer a BeautifulStoneSoup
class for parsing XML. To parse XML you pass in “xml” as the second argument to the BeautifulSoup
constructor. For the same reason, the BeautifulSoup
constructor no longer recognizes the isHTML
argument.
Beautiful Soup’s handling of empty-element XML tags has been improved. Previously when you parsed XML you had to explicitly say which tags were considered empty-element tags. The selfClosingTags
argument to the constructor is no longer recognized. Instead, Beautiful Soup considers any empty tag to be an empty-element tag. If you add a child to an empty-element tag, it stops being an empty-element tag.
Entities
An incoming HTML or XML entity is always converted into the corresponding Unicode character. Beautiful Soup 3 had a number of overlapping ways of dealing with entities, which have been removed. The BeautifulSoup
constructor no longer recognizes the smartQuotesTo
or convertEntities
arguments. (Unicode, Dammit still has smart_quotes_to
, but its default is now to turn smart quotes into Unicode.) The constants HTML_ENTITIES
, XML_ENTITIES
, and XHTML_ENTITIES
have been removed, since they configure a feature (transforming some but not all entities into Unicode characters) that no longer exists.
If you want to turn Unicode characters back into HTML entities on output, rather than turning them into UTF-8 characters, you need to use an output formatter.
Miscellaneous
Tag.string now operates recursively. If tag A contains a single tag B and nothing else, then A.string is the same as B.string. (Previously, it was None.)
Multi-valued attributes like class
have lists of strings as their values, not strings. This may affect the way you search by CSS class.
Tag
objects now implement the __hash__
method, such that two Tag
objects are considered equal if they generate the same markup. This may change your script’s behavior if you put Tag
objects into a dictionary or set.
If you pass one of the find*
methods both string and a tag-specific argument like name, Beautiful Soup will search for tags that match your tag-specific criteria and whose Tag.string matches your value for string. It will not find the strings themselves. Previously, Beautiful Soup ignored the tag-specific arguments and looked for strings.
The BeautifulSoup
constructor no longer recognizes the markupMassage argument. It’s now the parser’s responsibility to handle markup correctly.
The rarely-used alternate parser classes like ICantBelieveItsBeautifulSoup
and BeautifulSOAP
have been removed. It’s now the parser’s decision how to handle ambiguous markup.
The prettify()
method now returns a Unicode string, not a bytestring.
Reference : https://www.crummy.com/software/BeautifulSoup/bs4/doc/#translating-this-documentation
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