Explain XML Parser in Python
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XML stands for Markup Language eXtensible. It was designed to store and transport small to medium volumes of information and is commonly used for organized information sharing.
Python helps you to parse an XML document and change it. You must have the entire XML document in memory in order to parse the XML document. In this tutorial, we’ll see how we can load and parse XML files using the XML Minidom class in Python.
XML is a lightweight, open-source language that enables programmers to create software that, regardless of the operating system and/or development language, can be interpreted by other applications.
What’s XML in Python?
Just like HTML or SGML, the Extensible Markup Language (XML) is a markup language.
XML is extremely useful without needing a SQL-based backbone for keeping track of small to medium quantities of data.
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APIs and XML Parser Architectures in Python
A limited yet useful set of interfaces for XML work is given by the Python standard library.
The SAX and DOM interfaces are the two most common and broadly used APIs for XML data.
Easy XML API (SAX) in Python
You record callbacks for events of interest here and then let the parser go through the text. This is useful when your documents are big or you have memory constraints since it reads from the disk, it parses the file and the whole file is never stored in memory.
Domain Object Model (DOM) API in Python
When dealing with large files, SAX obviously can not process information as easily as DOM can. Using DOM exclusively, on the other hand, can really destroy your resources, especially if used on a lot of small files.
Since these two separate APIs basically complement each other, for large projects, there is no reason why you should not use both of them.
XML with SAX APIs parsing in Python
For event-driven XML parsing, SAX is a standard GUI. Generally speaking, parsing XML with SAX requires that you create your own ContentHandler by subclassing xml.sax.ContentHandler.
The basic tags and attributes of your XML flavor(s) are managed by your Content Handler. A Content Handler object offers techniques for managing different parsing events. Content Handler methods are named by its parser owner when it parses the XML text.
At the beginning and end of the XML file, the startDocument and endDocument methods are named. The character(text) method transfers the character data of the XML file via the text parameter.
At the start and end of each component, the ContentHandler is named.; otherwise, startElementNS and endElementNS are called, respectively. Here, the tag is the tag of the element and the attributes are the object of the attributes.
Let’s use a basic XML films.xml file as an input for all of our XML code examples.
We have a sample XML file generated that we are going to parse.
Step 1)
We can see the first name, last name, home, and area of expertise inside the file.
Step 2)
We will print out the “node name” of the document’s root and the “firstchild tagname” once we have parsed the document. The standard properties of the XML file are the tagname and the nodename.
Import the module xml.dom.minidom and declare a file to be parsed (myxml.xml)
This file has some basic employee details, such as first name, last name, home, skills, etc.
We use the XML Minidom decode function to load and parse the XML file.
Next, we have vector doc and doc gets the parse function output.
We want the nodename and child tagname to be printed out of the file, so we can declare it in the print function.
Run code
Prints the nodename of the XML file (#document) and the first child tag of the XML file.
Note:
The default XML dom names or resources are nodename and child tagname. In case you are not familiar with these types of conventions for naming.
Step 3)
We can also call and print the XML tag list from the XML text. The collection of abilities such as SQL, Python, Testing, and Business is printed out here.
Declare the vector expertise from which we can derive all of the employee’s expertise name
Using a dom-standard feature called “getElementsByTagName”
All the elements called skill will provide this.
Declare the loop through each of the skill tags.
Run the code- A list of four skills will be provided.
How to Create an XML Node in Python
By using the ‘createElement’ feature, we can create a new attribute and then append this new attribute or tag to existing XML tags. We have added a new ‘BigData’ tag to our XML format.
To add a new attribute (BigData) to the current XML name, you have to code it.
The XML tag must then be printed with new attributes appended to the original XML tag.
We use the code “doc.create elements” to add new XML and add it to the text.
This code introduces a new Ability Tag for our new “Big-data” attribute.
Add this Capability Tag to the First Child Document.
Run the code-the latest “big data” tag appears with the other list of skills.
Example XML Parser in Python
Python 2 Example
xml.dom.minidom.minidom import
Def Main()::def
# To load and parse an XML file, use the parse() feature
Doc =xml.dom.minidom.parse(“Myxml.xml”);
# The document node and the name of the first child tag are printed out.
Print doc.nodeName with doc.node
Print doc.firstChild.tagName to print
# Get a list of XML tags and print each of them out of the text.
Technical knowledge = doc.getElementsByTagName (“expertise”)
Print “percent d knowledge”: “percent knowledge.length”
For proficiency in expertise:
Skill.getAttribute for printing (“name”)
# Build and add a new XML tag to the text
Newexpertise = doc.createElementElementElement (“expertise”)
Attribute: newexpertise.setAttribute (“name”, “BigData”)
Doc.firstChild.appendChildAppendChild (newexpertise)
Print “ “
Technical knowledge = doc.getElementsByTagName (“expertise”)
Print “percent d knowledge”: “percent knowledge.length”
For proficiency in expertise:
Skill.getAttribute for printing (“name”)
If the name is == “__main__”::
Principal();
Python 3 Example
xml.dom.minidom.minidom import
Def Main()::def
# To load and parse an XML file, use the parse() feature
Doc =xml.dom.minidom.parse(“Myxml.xml”);
# The document node and the name of the first child tag are printed out.
Print a Print (doc.nodeName)
Print a Print (doc.firstChild.tagName)
# Get a list of XML tags and print each of them out of the text.
Technical knowledge = doc.getElementsByTagName (“expertise”)
Print a Print (“ percent d expertise:” percent expertise.length)
For proficiency in expertise:
(skill.getAttribute(“name”)) printing)
# Build and add a new XML tag to the text
Newexpertise = doc.createElementElementElement (“expertise”)
Attribute: newexpertise.setAttribute (“name”, “BigData”)
Doc.firstChild.appendChildAppendChild (newexpertise)
Print a Print (“ “)
Technical knowledge = doc.getElementsByTagName (“expertise”)
Print a Print (“ percent d expertise:” percent expertise.length)
For proficiency in expertise:
(skill.getAttribute(“name”)) printing)
When __name_ == “__main__”:
Principal();
How to Use Element Tree to parse XML in Python
Element Tree is an XML manipulation API. The easiest way to process XML files is via ElementTree.
As sample data, we are using the following XML document.
With <data>
The<items>
<name of item=”expertise1">SQL</item>
Expertise2> Python</item> <item name=’expertise2'>
With </items>
</datas>
XML Reading Using Element Tree:
We must first import a module from xml.etree.ElementTree.
As an ETT, import xml.etree.ElementTree
Now let’s fetch the element root:
Tree.getroot = root ()
The following is the full code above xml data for reading.
As an ETT
import xml.etree.ElementTree
= ET.parse(‘items.xml ‘) tree
Tree.getroot = root ()
Print(‘Data Expertise:’)
Elem at the root:
Subelem in elem: for:
Print a Print (subelem.text)
Conclusion
Python helps you to parse the whole XML document at once, not just one row at a time. You need to have the entire document in memory in order to parse XML documents. You can learn more about this parsing and other topics through Python online training.
