How to look at the previous record in a for-each

dep · October 30th, 2006, 02:46 PM

Is it possible to, while looping through a for-each, look at the previous record's value?

So that if I'm at position 2 and want to see the value of "symbol" for position 1, can this be done within the loop?

If no, how else can I accomplish this?

sorry for the noob question.

joefawcett · October 30th, 2006, 03:01 PM

An xsl:for-each is not a loop, all nodes in the sequence are processed in parallel, in an ideal world anyway...

If you show the structure of your XML and what you need they're will most likely be a simple XPath expression to retrieve the node you want.

--

Joe (Microsoft MVP - XML)

dep · October 30th, 2006, 03:37 PM

Code:

<EZMessage action="tool.coveredcall">
  <data>
    <spread>
      <symbol>SIRF</symbol>
      <expString>Oct 06</expString>
      <expTime>1161406800000</expTime>
      <returnRate>2.637</returnRate>
      <stockPrice>22.18</stockPrice>
      <callPrice>1.10</callPrice>
      <industryName>Semiconductors</industryName>
      <spc>100.0</spc>
      <leg>
        <side>B</side>
        <securityKey>SIRF:::S</securityKey>
      </leg>
      <leg>
        <side>S</side>
        <securityKey>QIR:20061021:225000:C</securityKey>
      </leg>
    </spread>
    <spread>
      <symbol>MLS</symbol>
      <expString>Oct 06</expString>
      <expTime>1161406800000</expTime>
      <returnRate>2.157</returnRate>
      <stockPrice>15.57</stockPrice>
      <callPrice>0.95</callPrice>
      <industryName>Real Estate</industryName>
      <spc>100.0</spc>
      <leg>
        <side>B</side>
        <securityKey>MLS:::S</securityKey>
      </leg>
      <leg>
        <side>S</side>
        <securityKey>MLS:20061021:150000:C</securityKey>
      </leg>
    </spread>
    ...
  </data>
</EZMessage>

basically I want to NOT display the node if the Symbol is the same as the previous node...

mhkay · October 30th, 2006, 04:10 PM

>I want to NOT display the node if the Symbol is the same as the previous node...

That's then a classic grouping problem, read all about it at http://www.jenitennison.com/xslt/grouping

Michael Kay
http://www.saxonica.com/
Author, XSLT Programmer's Reference and XPath 2.0 Programmer's Reference

dep · October 30th, 2006, 04:22 PM

Thank you :)

dep · October 30th, 2006, 04:33 PM

Code:

<xsl:key name="contacts-by-surname" match="contact" use="surname" />
<xsl:template match="records">
    <xsl:for-each select="contact[count(. | key('contacts-by-surname', surname)[1]) = 1]">
        <xsl:sort select="surname" />
        <xsl:value-of select="surname" />,<br />
        <xsl:for-each select="key('contacts-by-surname', surname)">
            <xsl:sort select="forename" />
            <xsl:value-of select="forename" /> (<xsl:value-of select="title" />)<br />
        </xsl:for-each>
    </xsl:for-each>
</xsl:template>

Oye... This is enough to make a newbie's head explode.

joefawcett · October 30th, 2006, 04:35 PM

I think that counts as a grouping problem, displaying data from the first occurence of each symbol. If using XSLT 1.0 then see the first post in this forum for links on grouping.

--

Joe (Microsoft MVP - XML)