is_nan throws an error if used on empty string
is_nan throws an error if used on empty string
jeremypoulter/emoncms,emoncms/emoncms,jeremypoulter/emoncms,inverse/emoncms,inverse/emoncms,thaipowertech/emoncms,jeremypoulter/emoncms,chaveiro/emoncms,emoncms/emoncms,jeremypoulter/emoncms,chaveiro/emoncms,inverse/emoncms,thaipowertech/emoncms,emoncms/emoncms,thaipowertech/emoncms,thaipowertech/emoncms,inverse/emoncms,chaveiro/emoncms,emoncms/emoncms,chaveiro/emoncms,emoncms/emoncms