xml2struct

Convert an xml file into a MATLAB structure for easy access to the data.

Description

Convert an xml file into a MATLAB structure for easy access to the data.

Acknowledgements

This file inspired Open Street Map Functions.

• MATLAB release: MATLAB 7.9 (R2009b)
• Other requirements: xmlread

[Yu]

Faster than xml_read, recommended!

[Erik]

Thanks for the file, however I'm having an issue with empty data fields.

If I have a 100x50 XML data set which I can easily import into Excel. However there are a few fields which are empty. For example at (5,35:40), the XML data is empty.

When I use the xml2struct and then try and create a cell array in the same format (100x50) the data in row 5 between 40:50, shifts to the 35:45 position and I'm left with 5 empty spaces from 45:50 and as such the data is misaligned.

Any idea on how to deal with empty fields in order to maintain their position in the original file?

Thanks!

[Rosie Vakasilimi]

i was just wondering if someone could just confirm what i am doing is correct. when i want to convert xml into a matlab array, i type:
data=xml2struct('name of the file i want to convert'); ? is that all?

[Michael Pelz-Sherman]

We are encountering the same issue reported by Raoul Herzog: Undefined function or method 'toCharArray' for input arguments of type 'double'. Is there a fix for this?

[Neill Weiss]

For the comment bug, @Sirius3, I changed the following code block from:

if (~strcmp(name,'#text') && ~strcmp(name,'#comment') && ~strcmp(name,'#cdata_dash_section'))
%XML allows the same elements to be defined multiple times,
%put each in a different cell
if (isfield(children,name))
if (~iscell(children.(name)))
%put existsing element into cell format
children.(name) = {children.(name)};
end
index = length(children.(name))+1;
%add new element
children.(name){index} = childs;
if(~isempty(fieldnames(text)))
children.(name){index} = text;
end
if(~isempty(attr))
children.(name){index}.('Attributes') = attr;
end
else
%add previously unknown (new) element to the structure
children.(name) = childs;
if(~isempty(text) && ~isempty(fieldnames(text)))
children.(name) = text;
end
if(~isempty(attr))
children.(name).('Attributes') = attr;
end
end
else

to

if (~strcmp(name,'#text') && ~strcmp(name,'#comment') && ~strcmp(name,'#cdata_dash_section'))
%XML allows the same elements to be defined multiple times,
%put each in a different cell
if (isfield(children,name))
if (~iscell(children.(name)))
%put existsing element into cell format
children.(name) = {children.(name)};
end
index = length(children.(name))+1;
%add new element
children.(name){index} = childs;
textFieldNames = fieldnames(text);
for t = 1:length(textFieldNames)
textFieldName = textFieldNames{t};
children.(name){index}.(textFieldName) = text.(textFieldName);
end
if(~isempty(attr))
children.(name){index}.('Attributes') = attr;
end
else
%add previously unknown (new) element to the structure
children.(name) = childs;
if(~isempty(text) && ~isempty(fieldnames(text)))
textFieldNames = fieldnames(text);
numTextFieldNames = length( textFieldNames );
for i = 1:numTextFieldNames
thisFieldName = textFieldNames{i};
children.(name).(thisFieldName) = text.(thisFieldName);
end
end
if(~isempty(attr))
children.(name).('Attributes') = attr;
end
end
else

Now, the children.(name) properties are not blown away when a comment is parsed.

[Sirius3]

bug: child nodes get lost, when there are comments between them. (line 95)

[Gledi]

First of all thank for the excellent code.
I have a "small" problem according to the cell. In you code, if there are more MORE THAN ONE child than you create a cell, otherwise not. What should I change to have the case: Even if the node has ONLY ONE child than I create a cell (with one element)

[Matthew]

Worked very well for me. Thank you so much.

[Raoul Herzog]

There seems to be a bug in xml2struct :
I can provide you the corresponding xml file if needed.

??? Undefined function or method 'toCharArray' for input arguments of type 'double'.

Error in ==> xml2struct>parseAttributes at 174
str = toCharArray(toString(item(theAttributes,count-1)))';

Error in ==> xml2struct>getNodeData at 141
attr = parseAttributes(theNode);

Error in ==> xml2struct>parseChildNodes at 72
[text,name,attr,childs,textflag] = getNodeData(theChild);

Error in ==> xml2struct>getNodeData at 147
[childs,text,textflag] = parseChildNodes(theNode);

Error in ==> xml2struct>parseChildNodes at 72
[text,name,attr,childs,textflag] = getNodeData(theChild);

Error in ==> xml2struct>getNodeData at 147
[childs,text,textflag] = parseChildNodes(theNode);

Error in ==> xml2struct>parseChildNodes at 72
[text,name,attr,childs,textflag] = getNodeData(theChild);

Error in ==> xml2struct>getNodeData at 147
[childs,text,textflag] = parseChildNodes(theNode);

Error in ==> xml2struct>parseChildNodes at 72
[text,name,attr,childs,textflag] = getNodeData(theChild);

Error in ==> xml2struct>getNodeData at 147
[childs,text,textflag] = parseChildNodes(theNode);

Error in ==> xml2struct>parseChildNodes at 72
[text,name,attr,childs,textflag] = getNodeData(theChild);

Error in ==> xml2struct>getNodeData at 147
[childs,text,textflag] = parseChildNodes(theNode);

Error in ==> xml2struct>parseChildNodes at 72
[text,name,attr,childs,textflag] = getNodeData(theChild);

Error in ==> xml2struct>getNodeData at 147
[childs,text,textflag] = parseChildNodes(theNode);

Error in ==> xml2struct>parseChildNodes at 72
[text,name,attr,childs,textflag] = getNodeData(theChild);

Error in ==> xml2struct>getNodeData at 147
[childs,text,textflag] = parseChildNodes(theNode);

Error in ==> xml2struct>parseChildNodes at 72
[text,name,attr,childs,textflag] = getNodeData(theChild);

Error in ==> xml2struct>getNodeData at 147
[childs,text,textflag] = parseChildNodes(theNode);

Error in ==> xml2struct>parseChildNodes at 72
[text,name,attr,childs,textflag] = getNodeData(theChild);

Error in ==> xml2struct>getNodeData at 147
[childs,text,textflag] = parseChildNodes(theNode);

Error in ==> xml2struct>parseChildNodes at 72
[text,name,attr,childs,textflag] = getNodeData(theChild);

Error in ==> xml2struct>getNodeData at 147
[childs,text,textflag] = parseChildNodes(theNode);

Error in ==> xml2struct>parseChildNodes at 72
[text,name,attr,childs,textflag] = getNodeData(theChild);

Error in ==> xml2struct at 57
s = parseChildNodes(xDoc);

[Xiaohu]

 

[Ivan Smirnov]

One of the problems that I personally encountered is that xml2struct can't handle CDATA blocks.

It can be easily fixed, replace line 67 with:
if (~strcmp(name,'#text') && ~strcmp(name,'#comment') && ~strcmp(name,'#cdata_dash_section'))
and line 94 with:
elseif (strcmp(name,'#text') || strcmp(name, '#cdata_dash_section'))

Works great otherwise, thanks.

[ali]

Excellent! I was pulling my hair to read to numbers from XML file and with this I did it in one minute

[Kevin Moerman]

Works great for small files. I tested it for some larger files with >100000 entries and this takes around 178 seconds.

[Kevin Moerman]

 

[Brad]

 

[Wouter Falkena]

Thank you for this suggestion Mr. Wanner. I have updated the file and it is currently under review by the MATLAB Central. It will appear here shortly.

[Adrian Wanner]

Thanks for your work.
You might want to speed up the attribute parsing by about 40% by replacing lines 152-154 by the following:
str=theAttributes.item(count-1).toString.toCharArray()';
k=strfind(str,'=');
attr_name = regexprep(str(1:(k(1)-1)),'[-:.]','_');
attributes.(attr_name) =str((k(1)+2):(end-1));

[Mark]

Thanks, your auto field naming system worked great for me to work with data parsed out from XML files.

[Bernard]

Thanks a lot! I finally came across a tool that can extract info from a ISO19115/19139 xml file.

[Joao Henriques]

Simple and works pretty well! The structures are a bit verbose but they're supposed to be parsed by my program anyway; any attempts to collapse some of the nested structures would only slow down the code (some similar submissions do this but are much slower). Thanks!

[Krishnan Suresh]

Thanks v. much! I used it to read a Collada file (geometry file Google Sketch-up). Worked like a charm!

[Wouter Falkena]

You are correct. I have removed the '.xml' extension assumption, unless the file can not be found. The update file is currently under review by MATLAB Central and should appear here soon.

[Mathieu]

Warning: all XML files haven't '.xml' extension

[Joanne]

Worked on the first try for loading an OSM data file.

[TideMan]

I was tearing my hair out trying to figure out how to automatically access one tiny piece of data in a .xml file until I found this routine.

[Yanai]