如何计算节点中的不同值？

How to count distinct values in a node in XSLT?

如何计算XSLT中节点中的不同值？

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

示例：我想计算Country节点中现有国家/地区的数量，在这种情况下，它将为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>

4 个解决方案

#1

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:

如果您有一个大文档，您可能希望使用通常用于分组的“Muenchian方法”来识别不同的节点。声明一个键，用于通过不同的值索引要计数的内容：

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

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

然后，您可以使用以下方式获取具有不同国家/地区的元素：

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

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

你可以通过在count（）函数的调用中包装它来计算它们。

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

当然在XSLT 2.0中，它就像它一样简单

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

#2

In XSLT 1.0 this isn't obvious, but the following should give you an idea of the requirement:

在XSLT 1.0中，这并不明显，但以下内容应该让您了解该要求：

count(//Artist_by_Country[not(Location_ID=preceding-sibling::Artist_by_Country/Location_ID)]/Location_ID)

The more elements in your XML the longer this takes, as it checks every single preceding sibling of every single element.

XML中的元素越多，所需的时间就越长，因为它会检查每个元素的每个前面的兄弟元素。

#3

Try something like this:

尝试这样的事情：

count(//Country[not(following::Country/text() = text())])

"Give me the count of all Country nodes without a following Country with matching text"

“给我所有国家节点的计数，没有跟随国家和匹配的文本”

The interesting bit of that expression, IMO, is the following axis.

该表达式的有趣位IMO是跟随轴。

You could probably also remove the first /text(), and replace the second with .

您也可以删除第一个/ text（），并用第二个替换。

#4

If you have control of the xml generation on the first occurence of a country you could add an attribute to the country node such as distinct='true' flag the country as "used" and not subsequently add the distinct attribute if you come across that country again.

如果您在国家的第一次出现时控制了xml生成，则可以向国家/地区节点添加属性，例如distinct ='true'将该国家标记为“已使用”，如果遇到该国家，则不会添加该属性国家了。

You could then do

那你可以做

<xsl:for-each select="Artists_by_Countries/Artist_by_Country/Country[@distinct='true']" />

#1