Find and replacing text in elementtree

Asked 29/7, 2013 at 8:30 Answered 29/7, 2013 at 9:21

i am very new to programming and python. I am trying to find and replace a text in an xml file. Here is my xml file

<?xml version="1.0" encoding="UTF-8"?>
<!--Arbortext, Inc., 1988-2008, v.4002-->
<!DOCTYPE doc PUBLIC "-//MYCOMPANY//DTD XSEIF 1/FAD 110 05 R5//EN"
 "XSEIF_R5.dtd">
<doc version="XSEIF R5"
xmlns="urn:x-mycompany:r2:reg-doc:1551-fad.110.05:en:*">
<meta-data></meta-data>
<front></front> 
<body>
<chl1><title xml:id="id_881i">Installation</title>
<p>To install SDK, perform the tasks mentioned in the following
table.</p>
<p><input>ln -s /sim/<var>user_id</var>/.VirtualBox $home/.VirtualBox</input
></p>
</chl1>
</body>
</doc>
 <?Pub *0000021917 0?>

I need to replace all entries of "virtual box" with "Xen". For this i tried Elementtree. But i dont know how to replace and write back to the file. Here is my try.

import xml.etree.ElementTree as ET
tree=ET.parse('C:/My_location/1_1531-CRA 119     1364_2.xml')
doc=tree.getroot()
iterator=doc.getiterator()
 for body in iterator:
    old_text=body.replace("Virtualbox", "Xen")

The texts are available in many sub tags under body.I got the method to remove the subelement and append a new element, but didnt get to replace only the texts.

Gebler answered 29/7, 2013 at 8:30 Comment(0)

Replace text, tail attributes.

import lxml.etree as ET

with open('1.xml', 'rb+') as f:
    tree = ET.parse(f)
    root = tree.getroot()
    for elem in root.getiterator():
        if elem.text:
            elem.text = elem.text.replace('VirtualBox', 'Xen')
        if elem.tail:
            elem.tail = elem.tail.replace('VirtualBox', 'Xen')

    f.seek(0)
    f.write(ET.tostring(tree, encoding='UTF-8', xml_declaration=True))
    f.truncate()

Sapsucker answered 29/7, 2013 at 9:6 Comment(2)

Hi, thanks for answer. But it neither throw any error nor replaces in the original file. I m confused what happened. Even it happened same for another script. Here it is. import xml.etree.ElementTree as ET from xml.etree.ElementTree import Element tree=ET.parse('C:/Users/epeeham/Desktop/Official/SSR-SIM/Test/1_1531-CRA 119 1364_2.xml') doc=tree.getroot() elem=Element("approved-by") elem.attrib["approved"] = "yes" i tried setting an attribute value from no to yes. But it didnt throw me an error and also didnt work. Is it a problem with my xml? – Gebler 29/7, 2013 at 9:52

@ShahulHameed, I updated the code. The updated code use external library lxml. – Sapsucker 29/7, 2013 at 14:58

Probably the simplest way is to do:

ifile = open('input_file','r')
ofile = open('output_file','w')
for line in ifile.readlines():
  ofile.write(line.replace('VirtualBox','Xen'))
ifile.close()
ofile.close()

Marjana answered 29/7, 2013 at 9:21 Comment(2)

Hi, thanks for your answer. I tried this way before the Eleementtree way. But my xml file was fully wiped out. The content becomes empty. dont know y – Gebler 29/7, 2013 at 10:3

It must work if you have correct permissions to read the input file and write to an output file. ifile must be different from ofile. – Marjana 30/7, 2013 at 8:18

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