How to get Matlab to read correct amount of xml nodes

Question

I\'m reading a simple xml file using matlab\'s xmlread internal function.

Answer 1

I felt that @cholland answer was good, but I didn't like the extra xml work. So here is a solution to strip the whitespace from a copy of the xml file which is the root cause of the unwanted elements.

fid = fopen('tmpCopy.xml','wt');
str = regexprep(fileread(filename),'[\n\r]+',' ');
str = regexprep(str,'>[\s]*<','><');
fprintf(fid,'%s', str);
fclose(fid);

Answer 2

The XML parser behind the scenes is creating #text nodes for all whitespace between the node elements. Whereever there is a newline or indentation it will create a #text node with the newline and following indentation spaces in the data portion of the node. So in the xml example you provided when it is parsing the child nodes of the "ref" element it returns 5 nodes

1. Node 1: #text with newline and indentation spaces
2. Node 2: "requestor" node which in turn has a #text child with "John Doe" in the data portion
3. Node 3: #text with newline and indentation spaces
4. Node 4: "project" node which in turn has a #text child with "X" in the data portion
5. Node 5: #text with newline and indentation spaces

This function removes all of these useless #text nodes for you. Note that if you intentionally have an xml element composed of nothing but whitespace then this function will remove it but for the 99.99% of xml cases this should work just fine.

function removeIndentNodes( childNodes )

numNodes = childNodes.getLength;
remList = [];
for i = numNodes:-1:1
   theChild = childNodes.item(i-1);
   if (theChild.hasChildNodes)
      removeIndentNodes(theChild.getChildNodes);
   else
      if ( theChild.getNodeType == theChild.TEXT_NODE && ...
           ~isempty(char(theChild.getData()))         && ...
           all(isspace(char(theChild.getData()))))
         remList(end+1) = i-1; % java indexing
      end
   end
end
for i = 1:length(remList)
   childNodes.removeChild(childNodes.item(remList(i)));
end

end

Call it like this

tree = xmlread( xmlfile );
removeIndentNodes( tree.getChildNodes );