[xsl] grouping and word counting

[marina <marina777uk@xxxxxxxxx>]

Hi,

I have an XML document that contains messages sent by
people to one another. Many of these messages in the
<MESSAGE> tags are repeated as they are sent by one
person to many others. 

XML Snippet:
--------------------------------------------------
<LOG>
   <SENT>
      <USER> 12345 </USER>
      <LOCATION> 55555 </LOCATION>
      <TARGET> 1 </TARGET>
      <TARGET_LOCATION> 23222 </TARGET_LOCATION>
      <MESSAGE> hello Fred </MESSAGE>
   </SENT>
   <SENT>
      <USER> 77777 </USER>
      <LOCATION> 76666 </LOCATION>
      <TARGET> 3 </TARGET>
      <TARGET_LOCATION> 34444 </TARGET_LOCATION>
      <MESSAGE> nice weather </MESSAGE>
   </SENT>
   <SENT>
      <USER> 77777 </USER>
      <LOCATION> 76666 </LOCATION>
      <TARGET> 4 </TARGET>
      <TARGET_LOCATION> 67777 </TARGET_LOCATION>
      <MESSAGE> nice weather </MESSAGE>
   </SENT>
   <SENT>
      <USER> 33333 </USER>
      <LOCATION> 12666 </LOCATION>
      <TARGET> 8 </TARGET>
      <TARGET_LOCATION> 98765 </TARGET_LOCATION>
      <MESSAGE> whats the latest news? </MESSAGE>
   </SENT>
   <SENT>
      <USER> 33333 </USER>
      <LOCATION> 12666 </LOCATION>
      <TARGET> 9 </TARGET>
      <TARGET_LOCATION> 46578 </TARGET_LOCATION>
      <MESSAGE> whats the latest news? </MESSAGE>
   </SENT>
</LOG>
--------------------------------------------------
What I need to do is:-

1) Find out how many messages over all were sent to 1,
2, 3 etc people.

As a duplicated message will always follow the
original, i.e. be the next <MESSAGE> tag of the
following sibling node, I'm thinking that the
stylesheet would start with the first message and keep
comparing siblings until it found one that was
different. Then it would just add the previous number
of sibling nodes? ( I probably need to use keys?)

2) For each of the total messages per group size,
calculate the average number of words. No idea on this
one I'm afraid!

So the desired output from the snippet above would be:
-

Group Size	Number of Messages 	Av Number Words
    1			1			2
    2			2			3
 (up to say 20) 

Many thanks in advance for any help,

Marina       




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