XPath - Operatori booleani

XPath definisce i seguenti operatori booleani da utilizzare con le espressioni XPath.

S.No. Operatore e descrizione
1

and

entrambe le condizioni devono essere soddisfatte
2

or

una qualsiasi delle condizioni da soddisfare
3

not()

funzione per verificare la condizione da non soddisfare.

Esempio

Questo esempio crea una tabella dell'elemento <student> con il suo attributo roll no e il suo figlio <firstname> ,<lastname> <nickname> e <marks> ripetendo ogni studente. Controlla che rollno sia 393 o 493 e quindi stampa i dettagli degli studenti.

students.xml

<?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>

students.xsl

<?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[(@rollno = 393) or ((@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>
            </table>
         </body>
      </html>
   </xsl:template>
</xsl:stylesheet>

Verifica l'output