SAX XML Parse Python error message

[goldtech]

SAX XML Parse Python error message
Hi,
My first attempt at SAX, but have an error message I need help with.

I cite the error message, code, and xml below.

Be grateful if anyone can tell me what the fix is.
Thanks.

>>>

Traceback (most recent call last):
File "C:\Python24\Li b\site-packages\python win\pywin\frame work
\scriptutils.py ", line 310, in RunScript
exec codeObject in __main__.__dict __
File "C:\pythonscrip ts\xml\parse3.p y", line 43, in ?
parser.parse(r' C:\perlscripts\ xml\Document2.k ml')
File "C:\Python24\li b\xml\sax\expat reader.py", line 107, in parse
xmlreader.Incre mentalParser.pa rse(self, source)
File "C:\Python24\li b\xml\sax\xmlre ader.py", line 123, in parse
self.feed(buffe r)
File "C:\Python24\li b\xml\sax\expat reader.py", line 207, in feed
self._parser.Pa rse(data, isFinal)
File "C:\Python24\li b\xml\sax\expat reader.py", line 303, in
end_element
self._cont_hand ler.endElement( name)
File "C:\pythonscrip ts\xml\parse3.p y", line 39, in endElement
print self.descriptio n, str(self.coordi nates)
AttributeError: G_Handler instance has no attribute 'coordinates'

>>>

Code:

from xml.sax import make_parser
from xml.sax.handler import ContentHandler
import string

class G_Handler(Conte ntHandler):

def __init__ (self):
self.isFolderEl ement = 0
self.isdescript ionElement = 0
self.iscoordina tesElement = 0

def startElement(se lf, name , attrs):
if name == 'Folder':
self.isFolderEl ement= 1
self.Folder = ""
if name == 'description':
self.isdescript ionElement= 1
self.descriptio n = ""
if name == 'coordinates':
self.iscoordina tesElement = 1
self.coordinate s = ""


def characters (self, ch):
if self.isFolderEl ement == 1:
self.Folder = ch
if self.isdescript ionElement == 1:
self.descriptio n = ch
if self.iscoordina tesElement == 1:
self.coordinate s = ch

def endElement(self , name):
if name == 'Folder':
self.isFolderEl ement = 0
if name == 'description':
self.isdescript ionElement= 0
if name == 'coordinates':
self.iscoordina tesElement = 0
print self.descriptio n, str(self.coordi nates)

parser = make_parser()
parser.setConte ntHandler(G_Han dler())
parser.parse(r' C:\perlscripts\ xml\Document2.k ml')



<?xml version="1.0" encoding="UTF-8"?>
<Folder>
<description>
abc
</description>
<coordinates>
-84.4, 33.7
</coordinates>
<description>
abc
</description>
<coordinates>
-86.7, 36.1
</coordinates>
</Folder>

[Stefan Behnel]

Re: SAX XML Parse Python error message

goldtech wrote:

My first attempt at SAX, but have an error message I need help with.

Just in case you prefer writing readable code over debugging SAX code into
existence, try lxml.

http://codespeak.net/lxml/

Here is a presentation you might find interesting.

http://codespeak.net/lxml/s5/lxml-ep2008.html

Stefan

[goldtech]

Re: SAX XML Parse Python error message

I would be grateful for support with the code I cited. It's not long
and fairly standard. I'm sure my error(s) would be glaring to more
experienced coders. I appreciated the "heads-up" about other options
but I would be grateful for help getting this code to run. Thanks



On Jul 13, 11:47 am, Stefan Behnel <stefan...@behn el.dewrote:

goldtech wrote:

My first attempt at SAX, but have an error message I need help with.

>
Just in case you prefer writing readable code over debugging SAX code into
existence, try lxml.
>

http://codespeak.net/lxml/

>
Here is a presentation you might find interesting.
>

http://codespeak.net/lxml/s5/lxml-ep2008.html

>
Stefan

[Waldemar Osuch]

Re: SAX XML Parse Python error message

On Jul 13, 3:00 pm, goldtech <goldt...@world post.comwrote:

I would be grateful for support with the code I cited. It's not long
and fairly standard. I'm sure my error(s) would be glaring to more
experienced coders. I appreciated the "heads-up" about other options
but I would be grateful for help getting this code to run. Thanks

Initialize self.coodinates in the __init__
or indent the "print self.descriptio n, str(self.coordi nates)"
one more level.
You have to remember that "endElement " is being called on the end
of every element. In your case it is called by </descriptionbut
the parser did not see <coordinatesyet .

In "def characters" you should be collecting the "ch" in a buffer.
It may be called multiple times for the same element.
Something like "self.descripti on += ch" would do for starters.

Also you do not need to convert self.coordinate s to string before
printing, it is already a string and even if it was not "print"
would convert it for you.

That's it for now :-) Others may spot more issues with
your code or my response.
On the positive side I really liked how you asked
the question. There was a short runnable example and traceback.

Waldemar

[goldtech]

Re: SAX XML Parse Python error message

On Jul 13, 5:30 pm, Waldemar Osuch <waldemar.os... @gmail.comwrote :

On Jul 13, 3:00 pm, goldtech <goldt...@world post.comwrote:
>

I would be grateful for support with the code I cited. It's not long
and fairly standard. I'm sure my error(s) would be glaring to more
experienced coders. I appreciated the "heads-up" about other options
but I would be grateful for help getting this code to run. Thanks

>
Initialize self.coodinates in the __init__
or indent the "print self.descriptio n, str(self.coordi nates)"
one more level.
You have to remember that "endElement " is being called on the end
of every element. In your case it is called by </descriptionbut
the parser did not see <coordinatesyet .
>
In "def characters" you should be collecting the "ch" in a buffer.
It may be called multiple times for the same element.
Something like "self.descripti on += ch" would do for starters.
>
Also you do not need to convert self.coordinate s to string before
printing, it is already a string and even if it was not "print"
would convert it for you.
>
That's it for now :-) Others may spot more issues with
your code or my response.
On the positive side I really liked how you asked
the question. There was a short runnable example and traceback.
>
Waldemar

Putting the print statements were they won't cause trouble and
using ...+= ch (vs. only =) in the character section fixed it:

....
def endElement(self , name):
....
if name == 'description':
self.isdescript ionElement= 0
print self.descriptio n
if name == 'coordinates':
self.iscoordina tesElement = 0
print self.coordinate s
....

I need to read your answer again carefully - I don't know if what I
did is best - but it seemed to fix it. Thank you for the clear and
cogent answer.

Lee G.

[Fredrik Lundh]

Re: SAX XML Parse Python error message

goldtech wrote:

I would be grateful for support with the code I cited. It's not long
and fairly standard. I'm sure my error(s) would be glaring to more
experienced coders. I appreciated the "heads-up" about other options
but I would be grateful for help getting this code to run. Thanks

For comparison, here's how an experienced Python programmer might prefer
to write your code:

import xml.etree.cElem entTree as ET

description = None # most recently seen description

for event, elem in ET.parse("somef ile.xml"):
if elem.tag == "descriptio n":
description = elem.text
elif elem.tag == "coordinate s":
print description.str ip(), elem.text.strip ()

You may want to ask yourself why you prefer to struggle with obsolete,
error-prone, and slow technology when there are more efficient tools
available in Python's standard library.

(the lxml library that Stefan linked to is a superset of xml.etree, in
case you want more XML features).

</F>