Advanced PDF sublist amount calculation

Advanced PDF templates transaction item sublist amount calculation. The below sample code shows the calculation of item amount for non-negative values. The lines with zero amounts are skipped and the positive values are calculated.

 <#if record.item?has_content>
   <#list record.item as item>
     <#if !(item.quantity?contains("-"))>
       <#assign subtotalvalue+=item.amount>
       </#if>
     </#list>
   </#if>