In this article, we will see how to parse XML and count instances of a particular node attribute in Python.
What is XML?
Extensible Markup Language (XML) Extensible Markup Language (XML) is a markup language that defines a set of rules for encoding documents in a format that is both human-readable and machine-readable. It is a markup language like HTML, and It is designed to store and transport data. Here, we will use built-in XML modules in python for parsing XML and then counting the instances of a node. We use ElementTree XML API and minidom API to parse our XML file.
XML code for a note is given below:
It should be saved as a country_data.xml file in the same directory.
XML
<?xml version="1.0"?><data> <country name="France"> <rank>1</rank> <year>2008</year> <gdppc>141100</gdppc> <neighbor name="Germany" direction="E"/> <neighbor name="Spain" direction="N"/> </country> <country name="Poland"> <rank>4</rank> <year>2011</year> <gdppc>59900</gdppc> <neighbor name="Germany" direction="W"/> </country> <country name="Italy"> <rank>68</rank> <year>2015</year> <gdppc>13600</gdppc> <neighbor name="France" direction="N"/> </country></data> |
Example 1:
In this example, We will use xml.etree.ElementTree module for parsing our XML file and storing in tree variable and after that we will find all the instances of a particular node attribute with the python findall() function of this module. Now we iterate over a list and check for a particular node attribute value if it matches then we will increment count as 1 to our variable.
Python3
# Importing our module import xml.etree.ElementTree as ET# Finding the Node Attribute with name tag # neighbor and name value as "Germany"Name_attribute = "France";# Parsing our xml file tree = ET.parse('country_data.xml')root = tree.getroot();# Counting the instance of Node attribute with findall NO_node = 0 ;for instance in root.findall('country/neighbor'): # Checking for the particular Node Attribute if instance.get('name') == Name_attribute: NO_node+=1;# Printing Number of nodesprint ("total instance of given node attribute is : ", NO_node) |
Output:
total instance of given node attribute is : 1
Example 2:
In this example, we will parse our XML file with the help of minidom module and assign this to the doc variable, getElementsByTagName() function returns a list of instances of a particular node. Now we iterate over a list and check for a particular node attribute value if it matches then we will increment count as 1 to our variable.
Python3
# Importing our module from xml.dom import minidom# Finding the node instance with name "Germany"Name_attribute = "Germany";# Parsing our xml file doc = minidom.parse('country_data.xml')root = doc.getElementsByTagName('neighbor')Number_attributes = 0;for i in root: # print ctypes.cast(i, ctypes.py_object).value if i.attributes['name'].value == Name_attribute: Number_attributes += 1; # Printing Number of nodesprint ("Total instance of Particular node attribute is : " ,Number_attributes) |
Output:
Total instance of Particular node attribute is : 2
