Re: [xsl] XSL For-Each Help!

[Wendell Piez <wapiez@xxxxxxxxxxxxxxxx>]

Rusty,

XSLT keys are very useful for this sort of thing.

Declare a key that returns ItemsAsSold elements based on the values 
of their Distributor children:

<xsl:key name="items-by-distributor" match="ItemAsSold" use="DistributorCode"/>

(You might need or want to qualify this further by matching only 
ItemAsSold elements with the criteria you want: 
match="ItemAsSold[CanOrderFlag='true'][CanShipFlag = 'true']".)

Invoking this key with a given value will return the set of all 
ItemAsSold elements (or all those with the given attribute values) 
whose DistributorCode is that value.

If you simply want a list of the unique DistributorCode values, get 
that by selecting all of them and filtering in those whose ItemAsSold 
parent is the first ItemAsSold with that value, as retrieved by the 
key. We commonly use a test on the generated id of an element (since 
it is unique to that element) to determine "node identity" in such cases.

In XPath this looks like:

//DistributorCode[generate-id(parent::ItemAsSold) =
                  generate-id(key('items-by-distributor',current())[1]) ]

which can be bound to a variable, iterated over or what have you.

Such use of the key() function is, indeed, the core of the "Muenchian 
method" of grouping in XSLT 1.0.

This is complex (and non-intuitive) enough that XPath 2.0 cuts the 
Gordian knot by providing us a distinct-values() function

distinct-values(//ItemAsSold[CanOrderFlag='true'][CanShipFlag = 
'true']/DistributorCode)

which returns a sequence of strings rather than a set of 
DistributorCode elements.

I hope this helps,
Wendell

At 03:17 PM 7/17/2006, you wrote:
> Hi All,
>
> Please see the below, I am in desperate need to
> resolve this issue and cannot figure it out for the
> life of me...
>
> ----Problem----:
> I am trying to obtain a distinct list of
> values('DistributorCodes') for each 'Item' from a
> large XML file containing thousands of items.
>
>
> ----Needs-----:
> I need to store the result in a variable within my
> stylesheet in order to satisfy other dependencies
>
>
> ---Sample XML-----:
> <Items>
>  <Item ID="1234">
>   <ItemsAsMade>
>       <ItemAsMade>
>          <SupplierCode>SHO</SupplierCode>
>          <ItemsAsSold>
>             <ItemAsSold>
>                 <DistributorCode>MEX</DistributorCode>
>                 <CanOrder>true</CanOrder>
>                 <CanShip>true</CanShip>
>             </ItemAsSold>
>             <ItemAsSold>
>                 <DistributorCode>CAN</DistributorCode>
>                 <CanOrder>false</CanOrder>
>                 <CanShip>false</CanShip>
>             </ItemAsSold>
>             <ItemAsSold>
>                 <DistributorCode>USA</DistributorCode>
>                 <CanOrder>true</CanOrder>
>                 <CanShip>true</CanShip>
>             </ItemAsSold>
>          </ItemsAsSold>
>       </ItemAsMade>
>       <ItemAsMade>
>          <SupplierCode>SHC</SupplierCode>
>          <ItemsAsSold>
>             <ItemAsSold>
>                 <DistributorCode>CAN</DistributorCode>
>                 <CanOrder>true</CanOrder>
>                 <CanShip>true</CanShip>
>             </ItemAsSold>
>             <ItemAsSold>
>                 <DistributorCode>USA</DistributorCode>
>                 <CanOrder>false</CanOrder>
>                 <CanShip>false</CanShip>
>             </ItemAsSold>
>             <ItemAsSold>
>                 <DistributorCode>MEX</DistributorCode>
>                 <CanOrder>false</CanOrder>
>                 <CanShip>false</CanShip>
>             </ItemAsSold>
>          </ItemsAsSold>
>       </ItemAsMade>
>   </ItemsAsMade>
>  </Item>
>    .....lots more Items...
> </Items>
>
>
> -----My Current Stylesheet snippet-----
> <xsl:variable name="distributorVal">
> <!-- only process distributorCodes if canShip and
> canOrder are both true -->
>    <xsl:for-each
> select="//ItemAsMade/ItemsAsSold/ItemAsSold[CanOrderFlag
> ='true'][CanShipFlag = 'true'][not(DistributorCode =
> preceding::DistributorCode)]/DistributorCode">
>           <xsl:value-of select="."/>
>           <xsl:text>,</xsl:text>
>    </xsl:for-each>
> </xsl:variable>
>
>
> ---Curent results based on above code------
> CAN
>
>
> ---Expected results---------------------
> MEX,CAN,USA
>
>
> ---Findings--------------------
> It seems that if any second <ItemAsMade> element
> within the  <ItemsAsMade> has a 'false' value it
> overrides the first <ItemAsMade> even if that one is
> set to true, where as if either <ItemAsMade> has both
> the canorder and canship flags set to true then that
> distributor should be extracted.
>
> ---Plea for Help--------------------
> PLEASE...PLEASE....can any of you UBER Gods of XSL
> help me!!
> I have been mucking with this for the past week and
> cannot figure it out!
>
>
> Thanks!!
>
> -Rusty