从和 xml 中选择最小值而不进行排序 [英] Selecting the lowest value from and xml without sorting
问题描述
我正在使用 xslt 将 xml 文档转换为 html 表，现在我想要做的是更改包含最低价格"值的单元格的背景颜色，而不对我的列表进行排序.
I'm transforming an xml document to an html table using xslt, and now what I want to do is to change the background color of the cell containing the lowest "price" value without sorting my list.
我是新来的，所以我正在做的是遵循 W3C 学校的例子.xml 文件如下所示:
I'm new on this, so what I'm doing is following the W3C schools examples. The xml file looks like this:
<?xml version="1.0" encoding="ISO-8859-1"?>
<!-- Edited by XMLSpy® -->
<catalog>
<cd>
<title>Empire Burlesque</title>
<artist>Bob Dylan</artist>
<country>USA</country>
<company>Columbia</company>
<price>10.90</price>
<year>1985</year>
</cd>
<cd>
<title>Black angel</title>
<artist>Savage Rose</artist>
<country>EU</country>
<company>Mega</company>
<price>11.90</price>
<year>1995</year>
</cd>
<cd>
<title>For the good times</title>
<artist>Kenny Rogers</artist>
<country>UK</country>
<company>Mucik Master</company>
<price>8.70</price>
<year>1995</year>
</cd>
</catalog>
我想要获得的东西与此类似，但没有按价格对列表中的元素进行排序.所以我想在XML文档中保持原来的顺序.
And what I want to obtain is something similar to this but without ordering the elements in the list by price. So I want to maintain the original order in the XML document.
<?xml version="1.0" encoding="ISO-8859-1"?>
<!-- Edited by XMLSpy® -->
<xsl:stylesheet version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:template match="/">
<html>
<body>
<h2>My CD Collection</h2>
<table border="1">
<tr bgcolor="#9acd32">
<th>Title</th>
<th>Artist</th>
<th>Price</th>
</tr>
<xsl:for-each select="catalog/cd">
<xsl:sort select="price" order="ascending" data-type="number"/>
<tr>
<td><xsl:value-of select="title"/></td>
<td><xsl:value-of select="artist"/></td>
<xsl:choose>
<xsl:when test="(position() = 1)">
<td bgcolor="#ff00ff">
<xsl:value-of select="price"/></td>
</xsl:when>
<xsl:otherwise>
<td><xsl:value-of select="price"/></td>
</xsl:otherwise>
</xsl:choose>
</tr>
</xsl:for-each>
</table>
</body>
</html>
</xsl:template>
</xsl:stylesheet>
预先感谢您的帮助.
我想我已经为我的问题找到了解决方案:
I think I have found a solution for my question:
<?xml version="1.0" encoding="ISO-8859-1"?>
<!-- Edited by XMLSpy® -->
<xsl:stylesheet version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:template match="/">
<html>
<body>
<h2>My CD Collection</h2>
<table border="1">
<tr bgcolor="#9acd32">
<th>Title</th>
<th>Artist</th>
<th>Price</th>
</tr>
<xsl:for-each select="catalog/cd">
<tr>
<td><xsl:value-of select="title"/></td>
<td><xsl:value-of select="artist"/></td>
<xsl:choose>
<xsl:when test="price=/catalog/cd/price[not(. > ../../cd/price)][1]">
<td bgcolor="#ff00ff">
<xsl:value-of select="price"/></td>
</xsl:when>
<xsl:otherwise>
<td><xsl:value-of select="price"/></td>
</xsl:otherwise>
</xsl:choose>
</tr>
</xsl:for-each>
</table>
</body>
</html>
</xsl:template>
推荐答案
您似乎已经回答了您的问题，但我将在这里介绍一些其他内容.
You seem to have answered your question already, but I will throw in a couple of other things in here.
(1) 通过在样式表或模板中添加一个变量进行一次计算，您可以通过 <cd/> 元素避免在每次迭代时重新计算最低价格:
(1) You can avoid re-calculating the minimum price at each iteration through the <cd/> elements by adding a variable to the stylesheet or the template to do the calculation once:
<xsl:variable name="least" select="math:min(/catalog/cd/price)"/>
(2) $least"变量声明使用 EXSLT math:min 函数(命名空间是 xmlns:math="http://exslt.org/math")，它可能对您的 XSLT 1.0 处理器可用.如果您有 2.0 处理器，则可以使用内置的min()".
(2) That "$least" variable declaration uses the EXSLT math:min function (namespace is xmlns:math="http://exslt.org/math"), which may be available to your XSLT 1.0 processor. If you have a 2.0 processor, you can use the built-in "min()".
如果不出意外，min() 函数对于下一个人来说更具可读性.
If nothing else, a min() function is more readable for the next person.
(3) 这纯粹是风格上的，但是您可以通过使用 xsl:attribute 来减少分支.
(3) This is purely stylistic, but you can reduce the branching a bit by using xsl:attribute.
<td>
<xsl:if test="price=$lowest">
<xsl:attribute name="bgcolor">#ff00ff</xsl:attribute>
</xsl:if>
<xsl:value-of select="price"/>
</td>
这篇关于从和 xml 中选择最小值而不进行排序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！
