How to use BeautifulSoup alongside with lxml parser In Python
For the purpose of reading and writing the xml file we would be using a Python library named BeautifulSoup. In order to install the library, type the following command into the terminal.
pip install beautifulsoup4
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 (used for parsing XML/HTML documents). lxml could be installed by running the following command in the command processor of your Operating system:
pip install lxml
Firstly we will learn how to read from an XML file. We would also parse data stored in it. Later we would learn how to create an XML file and write data to it.
Reading Data From an XML File
There are two steps required to parse a xml file:-
- Finding Tags
- Extracting from tags
Example:
XML File used:
Python3
from bs4 import BeautifulSoup# Reading the data inside the xml# file to a variable under the name # datawith open('dict.xml', 'r') as f: data = f.read()# Passing the stored data inside# the beautifulsoup parser, storing# the returned object Bs_data = BeautifulSoup(data, "xml")# Finding all instances of tag # `unique`b_unique = Bs_data.find_all('unique')print(b_unique)# Using find() to extract attributes # of the first instance of the tagb_name = Bs_data.find('child', {'name':'Frank'})print(b_name)# Extracting the data stored in a# specific attribute of the # `child` tagvalue = b_name.get('test')print(value) |
OUTPUT:
Writing an XML File
Writing a xml file is a primitive process, reason for that being the fact that xml files aren’t encoded in a special way. Modifying sections of a xml document requires one to parse through it at first. In the below code we would modify some sections of the aforementioned xml document.
Example:
Python3
from bs4 import BeautifulSoup# Reading data from the xml filewith open('dict.xml', 'r') as f: data = f.read()# Passing the data of the xml# file to the xml parser of# beautifulsoupbs_data = BeautifulSoup(data, 'xml')# A loop for replacing the value# of attribute `test` to WHAT !!# The tag is found by the clause# `bs_data.find_all('child', {'name':'Frank'})`for tag in bs_data.find_all('child', {'name':'Frank'}): tag['test'] = "WHAT !!"# Output the contents of the # modified xml fileprint(bs_data.prettify()) |
Output:
Reading and Writing XML Files in Python
Extensible Markup Language, commonly known as XML is a language designed specifically to be easy to interpret by both humans and computers altogether. The language defines a set of rules used to encode a document in a specific format. In this article, methods have been described to read and write XML files in python.
Note: In general, the process of reading the data from an XML file and analyzing its logical components is known as Parsing. Therefore, when we refer to reading a xml file we are referring to parsing the XML document.
In this article, we would take a look at two libraries that could be used for the purpose of xml parsing. They are:
- BeautifulSoup used alongside the lxml parser
- Elementtree library.
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