XSL "Is Numeric" too
Building on a previous post Oracle “Is Numeric” a similar thing is possible using XSLT (or more accurately, XPATH) too…
<xsl:if test="string-length(translate(node(),' +-.1234567890', ' ')) > 0">
<xsl:text>not numeric</xsl:text>
</xsl:if>
Not exactly ground breaking stuff, but something similar did turn out useful for extracting the non numerical area component of a post code (i.e. the SO bit of SO53 3RY).
substring-before(translate($postcode,'1234567890', '----------'),'-')
Which I thought was close enough to the oracle is numeric implementation to make comment.