xsl索引的递归循环节点 [英] xsl recursive loop node by index
问题描述
我创建了一个递归模板,用于从我的XML中获取前n个项目。
I have created a recursive template for getting the first n number of items from my XML.
它使用索引(计数器)就像我在for循环。现在我如何使用索引从我的XML中获取节点?
It uses an index(counter) just like how I would in a for loop. Now how can I get a node from my XML using the index?
我尝试过[position()= $ index]但是在尝试深入时它有奇怪的行为XML层次结构中的节点。
I have tried [position()=$index] but it had weird behaviour when trying to get deeper nodes in the XML hierarchy.
如果我有XML,例如:
If I have XML such as:
<0>
<1>
<2>item</2>
<2>item</2>
<2>item</2>
<2>item</2>
<2>item</2>
<2>item</2>
</1>
</0>
我希望能够计算并复制2,直到我有我想要的数量。
I want to be able to count through and copy the 2's until I have as many as I want.
推荐答案
您说要以n组为单位处理元素。以下XSLT 1.0解决方案:
You say you want to process your elements in groups of n. The following XSLT 1.0 solution does it:
<xsl:stylesheet
version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
>
<xsl:param name="pGroupCount" select="3" />
<xsl:template match="/lvl-0">
<xsl:copy>
<!-- select the nodes that start a group -->
<xsl:apply-templates mode="group" select="
lvl-1/lvl-2[position() mod $pGroupCount = 1]
" />
</xsl:copy>
</xsl:template>
<xsl:template match="lvl-2" mode="group">
<!-- select the nodes belong to the current group -->
<xsl:variable name="current-group" select="
. | following-sibling::lvl-2[position() < $pGroupCount]
" />
<!-- output the current group, you can also do calculations with it -->
<group id="{position()}">
<xsl:copy-of select="$current-group" />
</group>
</xsl:template>
</xsl:stylesheet>
当应用于此输入文档时:
When applied to this input document:
<lvl-0>
<lvl-1>
<lvl-2>item.0</lvl-2>
<lvl-2>item.1</lvl-2>
<lvl-2>item.2</lvl-2>
<lvl-2>item.3</lvl-2>
<lvl-2>item.4</lvl-2>
<lvl-2>item.5</lvl-2>
<a>foo</a><!-- to prove that position() calculations still work -->
<lvl-2>item.6</lvl-2>
<lvl-2>item.7</lvl-2>
<lvl-2>item.8</lvl-2>
<lvl-2>item.9</lvl-2>
</lvl-1>
</lvl-0>
生成以下输出:
<lvl-0>
<group id="1">
<lvl-2>item.0</lvl-2>
<lvl-2>item.1</lvl-2>
<lvl-2>item.2</lvl-2>
</group>
<group id="2">
<lvl-2>item.3</lvl-2>
<lvl-2>item.4</lvl-2>
<lvl-2>item.5</lvl-2>
</group>
<group id="3">
<lvl-2>item.6</lvl-2>
<lvl-2>item.7</lvl-2>
<lvl-2>item.8</lvl-2>
</group>
<group id="4">
<lvl-2>item.9</lvl-2>
</group>
</lvl-0>
要明白这一点,你必须知道如何 position()
有效。当像这样使用时:
To understand this you must know how position()
works. When used like this:
lvl-1/lvl-2[position() mod $pGroupCount = 1]
它指的是 lvl-2
中的节点各自的(!)父母。在这种情况下,只有一个父级,因此 item.0
的位置为1, item.9
的位置为10 。
it refers to the position of lvl-2
nodes within their respective (!) parent. In this case, there is only one parent, so item.0
has position 1 and item.9
has position 10.
当像这样使用时:
following-sibling::lvl-2[position() < $pGroupCount]
它指的是跟随兄弟的相对位置: :
轴。在这种情况下, item.1
在 item.0
方面的相对位置为1。 (基本上,这与上面的相同,只是沿着(隐含的) child ::
轴计算。)
it refers to the relative position along the following-sibling::
axis. In this context, item.1
would have a relative position of 1 in regard to item.0
. (Basically, this is the same as the above, which just counts along the (implicit) child::
axis.)
单独使用时,如下所示:
When used on its own, like here:
<group id="{position()}">
它指的是当前正在处理的批次中当前节点的位置。在我们的例子中,批处理由启动组的节点组成( item.0
, item.3
, item.6
, item.9
),因此从1到4。
it refers to the position of the current node in the batch that is being processed at the moment. In our case the "batch" consists of nodes that start a group (item.0
, item.3
, item.6
, item.9
), so it goes from 1 to 4.
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