| boolean() Function | |
| Converts its argument to a boolean value. | |
| Inputs | |
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An object. The object is converted to a boolean value. This conversion is described in the following subsection. |
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| Output | |
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The boolean value corresponding to the input object. Objects are converted to boolean values as follows:
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| Defined in | |
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XPath section 4.3, Boolean Functions. |
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| Example | |
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The following example demonstrates the results of invoking the boolean() function against a variety of argument types. Here's our XML document: <?xml version="1.0"?> <test> <p>This is a test XML document used by several of our sample stylesheets.</p> <question> <text>When completed, the Eiffel Tower was the tallest building in the world.</text> <true>Yes! The Eiffel Tower was the world's tallest building until 1932, when New York's Empire State Building opened. </true> <false>No, the Eiffel Tower was the world's tallest building for over 30 years.</false> </question> </test> We'll process this document with the following stylesheet:
<?xml version="1.0"?>
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:output method="text"/>
<xsl:variable name="newline">
<xsl:text>
</xsl:text>
</xsl:variable>
<xsl:template match="/">
<xsl:value-of select="$newline"/>
<xsl:text>Tests of the boolean() function:</xsl:text>
<xsl:value-of select="$newline"/>
<xsl:value-of select="$newline"/>
<xsl:choose>
<xsl:when test="boolean(true())">
<xsl:text> "boolean(true())" returned true!</xsl:text>
</xsl:when>
<xsl:otherwise>
<xsl:text> "boolean(true())" returned false!</xsl:text>
</xsl:otherwise>
</xsl:choose>
<xsl:value-of select="$newline"/>
<xsl:choose>
<xsl:when test="boolean(true)">
<xsl:text> "boolean(true)" returned true!</xsl:text>
</xsl:when>
<xsl:otherwise>
<xsl:text> "boolean(true)" returned false!</xsl:text>
</xsl:otherwise>
</xsl:choose>
<xsl:value-of select="$newline"/>
<xsl:choose>
<xsl:when test="boolean('false')">
<xsl:text> "boolean('false')" returned true!</xsl:text>
</xsl:when>
<xsl:otherwise>
<xsl:text> "boolean('false')" returned false!</xsl:text>
</xsl:otherwise>
</xsl:choose>
<xsl:value-of select="$newline"/>
<xsl:choose>
<xsl:when test="boolean('7')">
<xsl:text> "boolean('7')" returned true!</xsl:text>
</xsl:when>
<xsl:otherwise>
<xsl:text> "boolean('7')" returned false!</xsl:text>
</xsl:otherwise>
</xsl:choose>
<xsl:value-of select="$newline"/>
<xsl:choose>
<xsl:when test="boolean(/true)">
<xsl:text> "boolean(/true)" returned true!</xsl:text>
</xsl:when>
<xsl:otherwise>
<xsl:text> "boolean(/true)" returned false!</xsl:text>
</xsl:otherwise>
</xsl:choose>
<xsl:value-of select="$newline"/>
<xsl:choose>
<xsl:when test="boolean(//true)">
<xsl:text> "boolean(//true)" returned true!</xsl:text>
</xsl:when>
<xsl:otherwise>
<xsl:text> "boolean(//true)" returned false!</xsl:text>
</xsl:otherwise>
</xsl:choose>
</xsl:template>
</xsl:stylesheet>
Here are the results:
Tests of the boolean() function:
"boolean(true())" returned true!
"boolean(true)" returned false!
"boolean('false')" returned true!
"boolean('7')" returned true!
"boolean(/true)" returned false!
"boolean(//true)" returned true!
See Section 4.2.1.2 in Chapter 4 for more examples and information. |
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