Re: how to create variable by comparing two variables

> On 14 Oct 2018, at 21:16, Dave Lang emaildavelang@xxxxxxxxx
<xsl-list-service@xxxxxxxxxxxxxxxxxxxxxx> wrote:
>
> I think I did a poor job of explaining what I'm trying to do.
>
> I have two lists of jpg names: $jpg_few and $jpg_many.
>
> I know that there are jpg names in $jpg_many that are not in jpg_few, but
that's okay, I'm not interested in them.
>
> I'm trying to find what jpg names are in $jpg_few that are NOT in
$jpg_many.
>
> I thought I had tokenized $jpg_few and $jpg_many when I created them.
>
> When I try to create a new variable by using a "not" expression with
$jpg_few and $jpg_many, I get an error message re: "A sequence of more than
one item is not allowed as the first argument of fn:tokenize()".

That error can only come from an expression that calls tokenize(). It's
therefore clearly not your declaration of jpgs_in_xml_not_directories that's
at fault.
>
>
> I tried doing string-join to $jpg_few and $jpg_many before putting them in
the expression but that didn't work either.
>
> Here's the expression I'm trying to use to create a variable that shows
which jpg names from $jpg_few are NOT in $jpg_many.
>
> <xsl:variable name="jpgs_in_xml_not_directories" select="($jpg_few)[not(. =
$jpg_many)]"/>
>
> I think the problem is that I'm trying to do something with $jpg_few and
$jpg_many that I can't do because they're strings or something, but this is
where I get in over my head.

It's a good idea to add a type declaration to your variables, e.g.
as="xs:string*". This will help anyone reading your code (including you) to
see what you think should be in the value of the variable, and if your
assumptions are wrong then it will often lead to more focussed diagnostics.

Michael Kay
Saxonica