Re: Can I change variable contents.

<Tag value="X:Y">
</Tag>

Thanks,
Vikram

One general Question: If we can't change xsl:variable, then why it is named variable? is should be xsl:constant.

the use of the word "variable" matches its original use in mathematics
not the slightly strange use in imperative programming languages
that allow constructs such as
x = x + 1
but don't allow you to subtract x from both sides of that equation and
deduce
0 = 1

something like

<xsl:for-each select="Tag[starts-with(@value,'grade:')]">
<xsl:value-of select="substring-after(@value,'grade:')"/>
<xsl:text> </xsl:text>
</xsl:for-each> from grade

<xsl:for-each select="Tag[starts-with(@value,'sub:')]">
<xsl:value-of select="substring-after(@value,'sub:')"/>
<xsl:text> </xsl:text>
</xsl:for-each> from sub

seems to answer your request. note that not only do you not need to
update a variable, you don't need a variable at all.

David