I need a regular Expression for Starts with and ends with - regex

Question

I am looking for a regular expression for locating numerous expressions to find and replace. The expression looks like s360a__fieldname__c. I need to find all the instances where the s360a__ is then followed by the __c.
The issue is that it has to be within the one line so it is not finding a starting s360a__ and then the next __c which may be several lines below.
Here is an example of some of the xml I am changing.
<fields>
<fullName>s360a__AddressPreferredStreetAddressCity__c</fullName>
<deprecated>false</deprecated>
<externalId>false</externalId>
<label>Preferred Street City</label>
<length>255</length>
<required>false</required>
<trackFeedHistory>false</trackFeedHistory>
<trackHistory>false</trackHistory>
<type>Text</type>
<unique>false</unique>
</fields>
<fields>
<fullName>s360a__AddressPreferredStreetAddressCountry__c</fullName>
<deprecated>false</deprecated>
<externalId>false</externalId>
<label>Preferred Street Country</label>
<picklist>

Answer 1

You'd better of using a parser, combined with an xpath instead. Here's an example with PHP (can easily be adopted for e.g. Python as well). The idea is to load the DOM, then use a function to filter out elements (starts-with() and text() in this example):
<?php
$xml = '<fields>
<fullName>s360a__AddressPreferredStreetAddressCity__c</fullName>
<deprecated>false</deprecated>
<externalId>false</externalId>
<label>Preferred Street City</label>
<length>255</length>
<required>false</required>
<trackFeedHistory>false</trackFeedHistory>
<trackHistory>false</trackHistory>
<type>Text</type>
<unique>false</unique>
</fields>';
$dom = simplexml_load_string($xml);
// find everything where the text starts with 's360a_'
$fields = $dom->xpath("//*[starts-with(text(), 's360a_')]");
print_r($fields);
# s360a__AddressPreferredStreetAddressCity__c
The code checks if the text starts with s360a_. To actually check if it also ends with some specific string, you need to fiddle quite a bit (as the corresponding function ends-with() is not yet supported).
# check if the node text starts and ends with a specific string
$fields = $dom->xpath("//*[starts-with(., 's360a_') and substring(text(), string-length(text()) - string-length('_c') +1) = '_c']");
?>