有效的xslt条件增量 [英] efficient xslt conditional increment

问题描述

在此问题中，我问如何执行条件增量.提供的答案有效，但不适用于庞大的数据集.

In this question i asked how to perform a conditional increment. The provided answer worked, but does not scale well on huge data-sets.

输入:

<Users>
    <User>
        <id>1</id>
        <username>jack</username>
    </User>
    <User>
        <id>2</id>
        <username>bob</username>
    </User>
    <User>
        <id>3</id>
        <username>bob</username>
    </User>
    <User>
        <id>4</id>
        <username>jack</username>
    </User>
</Users>

所需的输出(最佳时间复杂度):

The desired output (in optimal time-complexity):

<Users>
   <User>
      <id>1</id>
      <username>jack01</username>
   </User>
   <User>
      <id>2</id>
      <username>bob01</username>
   </User>
   <User>
      <id>3</id>
      <username>bob02</username>
   </User>
   <User>
      <id>4</id>
      <username>jack02</username>
   </User>
</Users>

为此，很高兴

• 按用户名排序输入
每个用户
• • 先前的用户名等于当前的用户名时
    • 增量计数器和
    • 将用户名设置为"$ username $ counter"
    • sort input by username
    • for each user
      • when previous username is equals current username
        • increment counter and
        • set username to '$username$counter'
        • 将计数器设置为1

        有什么想法吗?

        推荐答案

        此转换准确地产生了指定的所需结果，并且效率很高(O(N)):

        <xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
         xmlns:ext="http://exslt.org/common" exclude-result-prefixes="ext">
         <xsl:output omit-xml-declaration="yes" indent="yes"/>
         <xsl:strip-space elements="*"/>
        
         <xsl:key name="kUserByName" match="User" use="username"/>
         <xsl:key name="kUByGid" match="u" use="@gid"/>
        
         <xsl:variable name="vOrderedByName">
          <xsl:for-each select=
          "/*/User[generate-id()=generate-id(key('kUserByName',username)[1])]">
             <xsl:for-each select="key('kUserByName',username)">
               <u gid="{generate-id()}" pos="{position()}"/>
             </xsl:for-each>
          </xsl:for-each>
         </xsl:variable>
        
          <xsl:template match="node()|@*">
             <xsl:copy>
               <xsl:apply-templates select="node()|@*"/>
             </xsl:copy>
         </xsl:template>
        
         <xsl:template match="username/text()">
             <xsl:value-of select="."/>
             <xsl:variable name="vGid" select="generate-id(../..)"/>
        
             <xsl:for-each select="ext:node-set($vOrderedByName)[1]">
              <xsl:value-of select="format-number(key('kUByGid', $vGid)/@pos, '00')"/>
             </xsl:for-each>
         </xsl:template>
        </xsl:stylesheet>
        

        应用于提供的XML文档:

        <Users>
            <User>
                <id>1</id>
                <username>jack</username>
            </User>
            <User>
                <id>2</id>
                <username>bob</username>
            </User>
            <User>
                <id>3</id>
                <username>bob</username>
            </User>
            <User>
                <id>4</id>
                <username>jack</username>
            </User>
        </Users>
        

        产生了所需的正确结果:

        <Users>
           <User>
              <id>1</id>
              <username>jack01</username>
           </User>
           <User>
              <id>2</id>
              <username>bob01</username>
           </User>
           <User>
              <id>3</id>
              <username>bob02</username>
           </User>
           <User>
              <id>4</id>
              <username>jack02</username>
           </User>
        </Users>
        

        这篇关于有效的xslt条件增量的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！