case-insensitive matching in xpath?

Question

For example, for the xml below

<CATALOG>
    <CD title="Empire Burlesque"/>
    <CD title="empire burlesque"/>
    <CD title="EMPIRE BURLESQUE"/>
    <CD title="EmPiRe BuRLeSQuE"/>
    <CD title="Others"/>
<CATALOG>

How to match the first 4 records with xpath like //CD[@title='empire burlesque']. Is there xpath function to do this? Other solutions like PHP function are also accepted.

Answer 1

XPath 2 has a lower-case (and upper-case) string function. That's not quite the same as case-insensitive, but hopefully it will be close enough:

//CD[lower-case(@title)='empire burlesque']

If you are using XPath 1, there is a hack using translate.

Answer 2

One possible PHP solution:

// load XML to SimpleXML
$x = simplexml_load_string($xmlstr);

// index it by title once
$index = array();
foreach ($x->CD as &$cd) {
  $title = strtolower((string)$cd['title']); 
  if (!array_key_exists($title, $index)) $index[$title] = array();
  $index[$title][] = &$cd;
}

// query the index 
$result = $index[strtolower("EMPIRE BURLESQUE")];

Answer 3

matches() is an XPATH 2.0 function that allows for case-insensitive matching.

One of the flags is i for case-insensitive matching.

The following XPATH using the matches() function with the case-insensitive flag:

//CD[matches(@title,'empire burlesque','i')]