在 Play 中获取当前循环的索引！2 Scala 模板
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Getting the index of the current loop in Play! 2 Scala template
提问by Romain Linsolas
In Play! 1, it was possible to get the current index inside a loop, with the following code:
在玩！1，可以使用以下代码获取循环内的当前索引：
#{list items:myItems, as: 'item'}
<li>Item ${item_index} is ${item}</li>
#{/list}
Is there an equivalent in Play2, to do something like that?
在 Play2 中是否有类似的东西来做这样的事情？
@for(item <- myItems) {
<li>Item ??? is @item</li>
}
Same question for the _isLastand _isFirst.
对于同样的问题_isLast和_isFirst。
ps: this questionis quite similar, but the solution implied to modify the code to return a Tuple (item, index)instead of just a list of item.
ps：这个问题很相似，但解决方案暗示修改代码以返回一个Tuple (item, index)而不是一个列表item。
回答by biesior
Yes, zipWithIndexis built-infeature fortunately there's more elegant way for using it:
是的，幸运的zipWithIndex是内置功能有更优雅的使用方式：
@for((item, index) <- myItems.zipWithIndex) {
<li>Item @index is @item</li>
}
The index is 0-based, so if you want to start from 1 instead of 0 just add 1 to currently displayed index:
索引是基于 0 的，因此如果您想从 1 而不是 0 开始，只需将 1 添加到当前显示的索引：
<li>Item @{index+1} is @item</li>
PS:Answering to your other question - no, there's no implicit indexes, _isFirst, _isLastproperties, anyway you can write simple Scala conditions inside the loop, basing on the values of the zipped index (Int) and sizeof the list (Intas well).
PS：回答您的另一个问题 - 不，没有隐式indexes, _isFirst,_isLast属性，无论如何您可以根据压缩索引 ( Int) 和size列表 ( )的值在循环内编写简单的 Scala 条件Int。
@for((item, index) <- myItems.zipWithIndex) {
<div style="margin-bottom:20px;">
Item @{index+1} is @item <br>
@if(index == 0) { First element }
@if(index == myItems.size-1) { Last element }
@if(index % 2 == 0) { ODD } else { EVEN }
</div>
}
回答by Dan Simon
The answer in the linked question is basically what you want to do. zipWithIndexconverts your list (which is a Seq[T]) into a Seq[(T, Int)]:
链接问题中的答案基本上是您想要做的。 zipWithIndex将您的列表（即 a Seq[T]）转换为 a Seq[(T, Int)]：
@list.zipWithIndex.foreach{case (item, index) =>
<li>Item @index is @item</li>
}
