如何计算节点中的不同值? [英] How to count distinct values in a node?

问题描述

如何在 XSLT 中计算节点中的不同值?

How to count distinct values in a node in XSLT?

示例:我想计算 Country 节点中现有国家/地区的数量，在本例中为 3.

Example: I want to count the number of existing countries in Country nodes, in this case, it would be 3.

<Artists_by_Countries>
    <Artist_by_Country>
        <Location_ID>62</Location_ID>
        <Artist_ID>212</Artist_ID>
        <Country>Argentina</Country>
    </Artist_by_Country>
    <Artist_by_Country>
        <Location_ID>4</Location_ID>
        <Artist_ID>108</Artist_ID>
        <Country>Australia</Country>
    </Artist_by_Country>
    <Artist_by_Country>
        <Location_ID>4</Location_ID>
        <Artist_ID>111</Artist_ID>
        <Country>Australia</Country>
    </Artist_by_Country>
    <Artist_by_Country>
        <Location_ID>12</Location_ID>
        <Artist_ID>78</Artist_ID>
        <Country>Germany</Country>
    </Artist_by_Country>
</Artists_by_Countries>

推荐答案

如果您有一个大文档，您可能想使用通常用于分组的Muenchian Method"来识别不同的节点.声明一个键，用不同的值索引你想要计数的东西:

If you have a large document, you probably want to use the "Muenchian Method", which is usually used for grouping, to identify the distinct nodes. Declare a key that indexes the things you want to count by the values that are distinct:

<xsl:key name="artists-by-country" match="Artist_by_Country" use="Country" />

然后您可以使用以下方法获取具有不同国家/地区的 元素:

Then you can get the <Artist_by_Country> elements that have distinct countries using:

/Artists_by_Countries
  /Artist_by_Country
    [generate-id(.) =
     generate-id(key('artists-by-country', Country)[1])]

并且您可以通过将其包装在对 count() 函数的调用中来计算它们.

and you can count them by wrapping that in a call to the count() function.

当然在 XSLT 2.0 中，就这么简单

Of course in XSLT 2.0, it's as simple as

count(distinct-values(/Artists_by_Countries/Artist_by_Country/Country))

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