How to get the result of the substraction of 2 attributes-CodePudding

Consider this simple xml

<books>
  <book>
    <price ht="100" ttc="120"/>
  </book>
  <book>
    <price ht="150" ttc="180"/>
  </book>
</books>

I want to list the substraction of ttc and ht for all book/price node (ttc - ht)

I know how to obtain the ttc: //book[price]/price/@ttc and the ht same way.

How to obtain the result of ttc - ht ?

CodePudding user response：

Try

//book/price/(./@ttc - ./@ht)

Given your sample xml, output is:

20
30

CodePudding user response：

To retrieve the difference per book element, you can use this XSL code in combination with the Identity template:

<xsl:template match="book">
    <xsl:copy>
        <xsl:value-of select="price/@ttc - price/@ht" />
    </xsl:copy>
</xsl:template>

It emits the difference for each <book> element.

To get the total difference of all <book> element's attributes, you can use the following XPath-1.0 expression:

<xsl:template match="books">
    <xsl:copy>
        <xsl:value-of select="sum(.//book/price/@ttc) - sum(.//book/price/@ht)" />
    </xsl:copy>
</xsl:template>

The core XPath-1.0 expression is, starting from the level of <books>, this one:

sum(.//book/price/@ttc) - sum(.//book/price/@ht)

This expression subtracts all @ht attributes from all @ttc attributes. The .// operator means, that all descendant elements starting from the current axis are selected. In the above XSLT code, the current axis is <books>.

So in the above example case, the result is 50.