Re: [xsl] Function that reduces the number of digits to the right of the decimal point?

["Michael Kay mike@xxxxxxxxxxxx" <xsl-list-service@xxxxxxxxxxxxxxxxxxxxxx>]

Do you absolutely want truncation (so 4.99 becomes 4.9) or will rounding do
(so 4.99 becomes 5.0)?

If rounding will do, then use round($x, -$desired-digits).

If you really want truncation then consider the "idiv" operator, for example
(4.99 * 10 idiv 10) gives 4.9: you can construct the value 10 as math:pow(10,
$desired-digits).

Michael Kay
Saxonica

> On 23 Jun 2020, at 15:28, Roger L Costello costello@xxxxxxxxx
<xsl-list-service@xxxxxxxxxxxxxxxxxxxxxx> wrote:
>
> Hi Folks,
>
> $num is a variable holding a decimal value.
>
> $desired-number-of-digits-after-decimal-point is a variable holding an
integer value.
>
> I want a function that reduces the number of digits to the right of the
decimal point in $num according to the value specified in
$desired-number-of-digits-after-decimal-point
>
> Example #1:
> $num = 42.366978
> $desired-number-of-digits-after-decimal-point = 2
> The result of applying the function is: 42.36
>
> Example #2:
> $num = 42.366978
> $desired-number-of-digits-after-decimal-point = 0
> The result of applying the function is: 42
>
> Below is one way to implement the function. Is there a better way? By
"better" I mean simpler, more correct.
>
> Also, is there a better name for the function?  By "better" I mean shorter,
more standardized. /Roger
> -----------------------------------------------------
> <xsl:function name="f:reduce-number-of-digits-after-decimal-point"
as="xs:string">
>    <xsl:param name="num" as="xs:string" />
>    <xsl:param name="desired-number-of-digits-after-decimal-point"
as="xs:integer" />
>
>    <xsl:variable name="whole-part" select="substring-before($num, '.')"/>
>    <xsl:variable name="fraction-part" select="substring-after($num, '.')"/>
>    <xsl:variable name="reduced-fraction-part"
select="substring($fraction-part, 1,
$desired-number-of-digits-after-decimal-point)"/>
>    <xsl:choose>
>        <xsl:when test="$desired-number-of-digits-after-decimal-point gt 0">
>            <xsl:value-of select="concat($whole-part, '.',
$reduced-fraction-part)"/>
>        </xsl:when>
>        <xsl:otherwise>
>            <xsl:value-of select="$whole-part"/>
>        </xsl:otherwise>
>    </xsl:choose>
> </xsl:function>