How to Replace a Child Node with a New Child Node in an XML Document using PHP

During programming in PHP there might be a need to replace some characters in a string to some other characters. Under such circumstances the replaceData function is used. This function is used to replace characters from a TextNode. The TextNode would be of type DOMCharacterData.

The function replaceData takes three parameters as inputs. First one is the offset, the second one is the count and the third one is the string that is to be used for replacement. The first parameter is the offset that serves as the starting point for the replacement to take place. The count gives the number of characters that is to be replaced and the third is the string that is used for replacement. If the offset or the count is negative this function throws a DOMException.

Consider the XML file candidate.xml given below:

<?xml version="1.0" encoding="UTF-8"?>
<candidate>
<candidatename>Robert</candidatename>
<candidatecity>New York</candidatecity>
<SSN>20072007</SSN>
<organization>XYZ Corp</organization>
</candidate>

In the above file we would create a new element called candidatedesignation and then create a TextNode with the text "Project Manager". Then we will replace the word "Project" as "General" using the replaceData function. The code for the above task is given below:

<?php
$xdoc = new DomDocument;
//You can replace the path to your xml file in the next line of code.
$xdoc->Load('C:/php/xmlfiles/candidate.xml');
$candidate = $xdoc->getElementsByTagName('candidate')->item(0);
$newElement = $xdoc ->createElement('candidatedesignation');
$txtNode = $xdoc ->createTextNode ("Project Manager");
$txtNode->replaceData(1,7,'General');
$newElement -> appendChild($txtNode);
$candidate -> appendChild($newElement);
//Save the file to any name of your choice.
$test = $xdoc->save("C:/php/xml_files/candidate2.xml");
echo "<B>Text Replaced<B>"
?>

The above code in PHP creates a new element name candidatedesignation and then creates a TextNode with the text "Project Manager". Then the replaceData function in PHP replaces the data "Project" as "General". We append this new element to the xml file and then save it in the name of candidate2.xml.

Upon execution of this code, you can open the file candidate2.xml. The content of that file would be something like given hereunder:

<?xml version="1.0" encoding="UTF-8"?>
<candidate>
<candidatename>Robert</candidatename>
<candidatecity>New York</candidatecity>
<SSN>20072007</SSN>
<organization>XYZ Corp</organization>
<candidatedesignation>General Manager</candidatedesignation>
</candidate>

Thus we can use the replaceData function in PHP to replace data in a textNode while working on an XML file.