谓词是指用方括号写的XPath表达式.它指的是为某些条件限制节点集中的选定节点.例如，
| S.No. | Predicate&描述 |
|---|---|
| 1 | /class/student [1] 选择第一个学生元素，它是类元素的子元素. |
| 2 | /class/student [last()] 选择最后一个学生元素，它是类元素的子元素. |
| 3 | /class/student [@rolllno = 493] 使用rollno 493选择student元素. |
| 4 | /class/student [marks> 85] 选择带有标记的学生元素> 85. |
此示例创建一个表< student>元素及其细节，通过迭代每个学生.它计算学生节点的位置，然后打印学生的详细信息以及序列号.
<?xml version = "1.0"?> <?xml-stylesheet type = "text/xsl" href = "students.xsl"?> <class> <student rollno = "393"> <firstname>Dinkar</firstname> <lastname>Kad</lastname> <nickname>Dinkar</nickname> <marks>85</marks> </student> <student rollno = "493"> <firstname>Vaneet</firstname> <lastname>Gupta</lastname> <nickname>Vinni</nickname> <marks>95</marks> </student> <student rollno = "593"> <firstname>Jasvir</firstname> <lastname>Singh</lastname> <nickname>Jazz</nickname> <marks>90</marks> </student> </class>
<?xml version = "1.0" encoding = "UTF-8"?> <xsl:stylesheet version = "1.0" xmlns:xsl = "http://www.w3.org/1999/XSL/Transform"> <xsl:template match = "/"> <html> <body> <h2>Students</h2> <table border = "1"> <tr bgcolor = "#9acd32"> <th>Roll No</th> <th>First Name</th> <th>Last Name</th> <th>Nick Name</th> <th>Marks</th> </tr> <xsl:for-each select = "/class/student[1]"> <tr> <td><xsl:value-of select = "@rollno"/></td> <td><xsl:value-of select = "firstname"/></td> <td><xsl:value-of select = "lastname"/></td> <td><xsl:value-of select = "nickname"/></td> <td><xsl:value-of select = "marks"/></td> </tr> </xsl:for-each> <xsl:for-each select = "/class/student[last()]"> <tr> <td><xsl:value-of select = "@rollno"/></td> <td><xsl:value-of select = "firstname"/></td> <td><xsl:value-of select = "lastname"/></td> <td><xsl:value-of select = "nickname"/></td> <td><xsl:value-of select = "marks"/></td> </tr> </xsl:for-each> <xsl:for-each select = "/class/student[@rollno = 493]"> <tr> <td><xsl:value-of select = "@rollno"/></td> <td><xsl:value-of select = "firstname"/></td> <td><xsl:value-of select = "lastname"/></td> <td><xsl:value-of select = "nickname"/></td> <td><xsl:value-of select = "marks"/></td> </tr> </xsl:for-each> <xsl:for-each select = "/class/student[marks > 85]"> <tr> <td><xsl:value-of select = "@rollno"/></td> <td><xsl:value-of select = "firstname"/></td> <td><xsl:value-of select = "lastname"/></td> <td><xsl:value-of select = "nickname"/></td> <td><xsl:value-of select = "marks"/></td> </tr> </xsl:for-each> </table> </body> </html> </xsl:template> </xsl:stylesheet>
