如何检查xslt中的上一个节点值？

Question

I have this xml where I'm getting repeated node set.I have to print it just one time. So I was thinking to compare the value with previous node set value and if it doesn't match then print it.

this is my code:-

<xsl:for-each select="Details">
<xsl:variable name="pos" select="position()"/>
    <xsl:if test="preceding-sibling::Details/Value[$pos] !=current()">
    <xsl:variable name="sign" select="'Y'"/>
    </xsl:if> 
</xsl:for>

Input XML:-

<Details>
    <Value>10</Value>
    <name>A</name>
</Details>
<Details>
    <Value>10</Value>
    <name>A</name> 
</Details>
<Details>
    <Value>20</Value>
    <name>B</name> 
</Details>
<Details>
    <Value>20</Value>
    <name>B</name> 
</Details>
<Details>
    <Value>30</Value>
    <name>C</name> 
</Details>
<Details>
    <Value>30</Value>
    <name>C</name> 
</Details>
<Details>
    <Value>30</Value>
    <name>C</name> 
</Details>

My output should be :-

<Details>
    <Value>10</Value>
    <name>A</name>
</Details>
<Details>
    <Value>20</Value>
    <name>B</name> 
</Details>
<Details>
    <Value>30</Value>
    <name>C</name> 
</Details>

So here it compares the value of

<Value> 

of current node with previous 'Value'. If it is unequal ex: 10<>20 then it should print 20s node set

Please help me with correct usage of preceding sibling or any other alternate. please note that the value of is not static.it might change in other xml so no hard coding. Thanks in advance

Answer 1

To implement your logic, you could simply do:

<xsl:copy-of select="Details[not(Value = preceding-sibling::Details[1]/Value)]"/>

However, this assumes the original XML is sorted; otherwise you will get duplicates when the same value appears again outside its first block. If that's not what you want, then use Muenchian grouping instead - it will be more efficient, too.

Answer 2

I am pretty sure that you are searching this:

<xsl:for-each-group select="Details" group-by=".">
    <xsl:copy-of select="."/>
</xsl:for-each-group>

Alternative to this would be something like this How to select unique nodes