How to get iterator's index in Play's template?

问题

I want to use a counter in a loop, so each table's row has its unique id attribute which indicates the current loop iteration. How can I access the current index? (in sample code marked as ITERATOR_HERE)

<table id="table_id" class="display">
<thead>
    <th>Key</th>
    <th>Value</th>      
    <th></th>
</thead>
<tbody>
    #{list items:paras, as:'elem' }
    <tr>
        <td id="ITERATOR_HERE">${elem.sendAllKey}</td>
        <td>${elem.sendAllValue}</td>               
        <td>button</td>             
    </tr>       
    #{/list}
</tbody>    
</table>

回答1:

The list tag creates a variable varname_index containing the current iteration number. See the tag reference for more information ;)

So, you snippet becomes:

#{list items:paras, as:'elem' }
<tr>
    <td id="ITERATOR_${elem_index}">${elem.sendAllKey}</td>
    <td>${elem.sendAllValue}</td>               
    <td>button</td>             
</tr>       
#{/list}

来源：https://stackoverflow.com/questions/12923208/how-to-get-iterators-index-in-plays-template