How do I StringReplace a value that changes?

[computergroove]

I have an xml file with the string "/merchant/poslogin.php?key=20000209_432</url>" and my script changes the value of 20000209_432. If I need to change it again I want to search for the string "/merchant/poslogin.php?key=" and tell autoit to count 27 characters from the string and replace the next 12 digits with my inputbox value. How can I tell StringReplace to start 27 digits from the string being replaced?

$NewCustomerID = StringReplace($chars, "2000293", $CustomerID) <-- Here
    $NewCustomerPin = StringReplace($NewCustomerID, "432", $CustomerPin)
    FileOpen("tiapp.xml", 2)
    FileWrite("tiapp.xml", $NewCustomerPin)
    FileClose($xmlfile)
    Exit

[somdcomputerguy]

I believe the StringTrimRight() function will do some good here.

[computergroove]

OK that worked out good. Here is my final code:

$NewCustomerID = StringReplace($chars, 553, $CustomerID) ;Repaces the Customer ID in tiapp.xml
    $NewCustomerData = StringReplace($NewCustomerID, 562, $CustomerPin) ;NewCustomerData hold the properly modified xml data
    FileOpen("tiapp.xml", 2)
    FileWrite("tiapp.xml", $NewCustomerData)
    FileClose($xmlfile)
    Exit

Edited January 11, 2011 by computergroove

[JohnOne]

heres another way.

#include <String.au3>

$sString = "/merchant/poslogin.php?key=20000209_432</url>"
$sID = _StringBetween($sString,"key=","</url>")
$sNewString = StringReplace($sString,$sID[0],"newKey")
MsgBox(0,"",$sNewString)