Append text to an XML file using Python element tree library

Question

I need to Create an XML file which takes N as an input from user and looks like this (here, N=3):

<test name="test1">                                                                
    <parameter name="username" value="bhusriva1" />  
    <classes>
        <class name="bhuv.mllab.tests.DensityTest" />
    </classes>
</test>
<test name="test2">
    <parameter name="username" value="bhusriva2" />
    <classes>
        <class name="bhuv.mllab.tests.DensityTest" />
    </classes>
</test>
<test name="test3">
    <parameter name="username" value="bhusriva3" />
    <classes>
        <class name="bhuv.mllab.tests.DensityTest" />
    </classes>
</test> 

So, in order to make this, I have created the following code, as shown below:

from xml.etree.ElementTree import ElementTree
from xml.etree.ElementTree import Element
import xml.etree.ElementTree as etree

#Number of users to create: Edit this part
N_users = 1

#Counter to terminate the loop and ID's
counter = 0
usr_num = 1

root = Element('test')
root.text = '<parameter name="username" value="bhusriva1" />'
tree = ElementTree(root)
name = Element('classes')
root.append(name)
name.text = '\n<class name="bhuv.mllab.tests.DensityTest" />\n'
root.set('name', 'test1')
print(etree.tostring(root))
tree.write(open('create_users_multi_browser.xml', 'w'))

while (N_users - 1) > counter:
    counter = counter + 1
    usr_num = usr_num + 1
    root = Element('test')
    temp1 = "<parameter name=" + "\"" + "username"+ "\"" + " value=" + "\"" + "bhusriva" + str(usr_num) + "\"" +" />"  
    root.text = temp1
    tree = ElementTree(root)
    name = Element('classes')
    root.append(name)
    name.text = '<class name="bhuv.mllab.tests.DensityTest" />'
    temp2 = "test" + str(usr_num)
    root.set('name', temp2)
    print(etree.tostring(root))
    tree.write(open("create_users_multi_browser.xml", "a"))

Here, for N_users = 1, the code is working fine but for N_users > 1, it is giving following output in internet explorer:

<parameter name="username" value="bhusriva1" /> <class name="bhuv.mllab.tests.DensityTest" />

So, what is needed to be corrected in the code? A completely new code with some different library usage is also fine with me.

Answer 1

A couple of issues with your code. First, if you use root.text, then the < and > get replaced by the string escape versions ( &gt and &lt ). Secondly, you don't have to maintain so many counters. Python does it for you directly! If we fix these 2 issues (I've added comments to explain what's going on) and clean up the logic a little then we get the following:

 from xml.etree.ElementTree import Element
 from xml.etree.ElementTree import SubElement
 import xml.etree.ElementTree as etree

 # Number of users to create: Edit this part
 users = 3

 op = ""
 for i in xrange(1, users + 1):
     # Create test element
     root = Element('test')
     root.set('name', 'test' + str(i))

     # Create parameter element
     params = SubElement(root, 'parameter')
     params.set('name' , 'username')
     params.set('value', 'bhusriva' + str(i))

     # Create classes element
     classes = SubElement(root, 'classes')

     # Add class subelement 
     class_element = SubElement(classes, 'class')
     class_element.set('name', 'bhuv.mllab.tests.DensityTest')

     # Add output to string
     op = op + etree.tostring(root)

 # Write output to file
 with open('create_users_multi_browser.xml', 'w') as f:
     f.write(op)

Running this gives the output:

<test name="test1">
  <parameter name="username" value="bhusriva1" />
  <classes>
    <class name="bhuv.mllab.tests.DensityTest" />
  </classes>
</test>
<test name="test2">
  <parameter name="username" value="bhusriva2" />
  <classes>
    <class name="bhuv.mllab.tests.DensityTest" />
  </classes>
</test>
<test name="test3">
  <parameter name="username" value="bhusriva3" />
  <classes>
    <class name="bhuv.mllab.tests.DensityTest" />
  </classes>
</test>

Hope this helps!