Formatting scientific number representation in xsl

Question

I have the following value in my XML -1.8959581529998104E-4. I want to format this to the exact number it should be using XSL to give me -0.000189595815299981.

format-number(-1.8959581529998104E-4,'0.000000;-0.000000') gives me NaN.

Any ideas?

Cheers

Andez

Solution 1

This is based on user357812 answer. But I made it act like a function and handle non-scientific notation

<xsl:template name="convertSciToNumString" >
    <xsl:param name="inputVal" select="0"/>
    <xsl:variable name="vExponent" select="substring-after($inputVal,'E')"/>
    <xsl:variable name="vMantissa" select="substring-before($inputVal,'E')"/>
    <xsl:variable name="vFactor"
         select="substring('100000000000000000000000000000000000000000000',
                           1, substring($vExponent,2) + 1)"/>
    <xsl:choose>
        <xsl:when test="number($inputVal)=$inputVal">
            <xsl:value-of select="$inputVal"/>
        </xsl:when>
        <xsl:when test="starts-with($vExponent,'-')">
            <xsl:value-of select="format-number($vMantissa div $vFactor, '#0.#############')"/>
        </xsl:when>
        <xsl:otherwise>
            <xsl:value-of select="format-number($vMantissa * $vFactor, '#0.#############')"/>
        </xsl:otherwise>
    </xsl:choose>
</xsl:template>

Usage:

<xsl:template match="X">
    <X>
        <xsl:call-template name="convertSciToNumString">
            <xsl:with-param name="inputVal" select="text()"/>
        </xsl:call-template>
    </X>    
</xsl:template>

This should handle a mix of scientific notation and decimal values.

Solution 2

The logic doesn't appear to work correctly in the above answers by Moop and user357812 when determining vFactor in one particular scenario.

If vExponent is a single-digit positive number (without a preceding '+' sign), then vFactor is set to an empty string. This is because an assumption was made that the 1st character of vExponent would be a plus/minus sign and therefore the 2nd character onwards were of interest. The vMantissa variable is then multiplied by an empty string which results in the template outputting NaN.

If vExponent is a multi-digit positive number (without a preceding '+' sign), then vFactor is set to an incorrect value. Because of the aforementioned assumption, the 1st digit is ignored and the vMantissa is then multiplied by an incorrect vFactor.

Therefore, I've modified the previously posted code a little so that it can handle scientific numbers of the forms: 2E-4, 2E+4 and 2E4.

<xsl:template name="convertSciToNumString" >
    <xsl:param name="inputVal" select="0"/>
    <xsl:variable name="vMantissa" select="substring-before(., 'E')"/>
    <xsl:variable name="vExponent" select="substring-after(., 'E')"/>
    <xsl:variable name="vExponentAbs" select="translate($vExponent, '-', '')"/>
    <xsl:variable name="vFactor" select="substring('100000000000000000000000000000000000000000000', 1, substring($vExponentAbs, 1) + 1)"/>
    <xsl:choose>
        <xsl:when test="number($inputVal)=$inputVal">
            <xsl:value-of select="$inputVal"/>
        </xsl:when>
        <xsl:when test="starts-with($vExponent,'-')">
            <xsl:value-of select="format-number($vMantissa div $vFactor, '#0.#############')"/>
        </xsl:when>
        <xsl:otherwise>         
            <xsl:value-of select="format-number($vMantissa * $vFactor, '#0.#############')"/>
        </xsl:otherwise>
    </xsl:choose>
</xsl:template>

Solution 3

Another possible workaround without a template:

<xsl:stylesheet version="1.0" ... xmlns:java="http://xml.apache.org/xslt/java">
...
<xsl:value-of select="format-number(java:java.lang.Double.parseDouble('1E-6'), '0.000')"/>