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Yet Another XML parser with the power of event-based memory-safe mechanism.

Project description

Yet Another XML parser is a powerful event-based memory-efficient Python module. It analyses the XML stream node by node and builds subtrees only if it is really needed.

In case of record-oriented XML input (when some subtree structure is repeated many times), it processes the file in a sequential manner similar to that of SAX. However, conditions can be defined which trigger a DOM like processing where subtrees are created.

This method is also efficient on very large data (which do not fit into the memory) both in terms of storage and computational time complexity.


YAX uses Python 3.x and above. It doesn’t depend on any third party module. However, if you have lxml installed you can use it as back-end. (See the documentation about performance.)


  • Download as a zip archive, uncompress and use it.
  • pip3 install yax
  • (Soon…) Downolad the deb package and install it.


A simple example which prints all the elements with tagname “a” and containing “href” attribute:

import yax

yr = yax.YAXReader(open("file.xml"))
yr.find("a", {"href": True}).calls(
    lambda e, i: print(yax.element_to_string(e, with_tail=False))  # with_tail only whith lxml!

A bit more complex example which filters a gpx record. It prints the elevation values of the trackpoints in a specified area:

import yax

yr = yax.YAXReader(open("route.gpx"))
yr.find("trkpt", {"lat": lambda v: 47 < float(v) < 48,
                  "lon": lambda v: 16 < float(v) < 17},
        ).calls(lambda e, i: print(e.find("ele").text))

This example shows that it would be erease all unneccessary children from the subtree to save memory but in this case we need the child called “ele”. For more example or the complete reference see the documentation.

See also

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