Thymeleaf - How to loop a list by index

Thymeleaf th:each allows you to declare an iteration status variable

<span th:each="task,iter : ${foo.tasks}">

Then in the loop you can refer to iter.index and iter.size.

See Tutorial: Using Thymeleaf - 6.2 Keeping iteration status.

Thymeleaf always declares implicit iteration status variable if we omit it.

<span th:each="task : ${foo.tasks}">
    <span th:text="${taskStat.index} + ': ' + ${task.name}"></span>
</span>

Here, the status variable name is taskStat which is the aggregation of variable task and the suffix Stat.

Then in the loop, we can refer to taskStat.index, taskStat.size, taskStat.count, taskStat.even and taskStat.odd, taskStat.first and taskStat.last.

^{Source: Tutorial: Using Thymeleaf - 6.2 Keeping iteration status}