Evaluating XPath Expresssions

XPath Result of XPath Evaluation
count((1, 2, 3)) 
3
count(('red', 'white', 'blue')) 
3
count(//planet) 
3
count((//planet, (1, 2, 3), ('red', 'white', 'blue'))) 
9

The XML Document

<planets>
    <planet>
        <name>Mercury</name>
        <mass units="(Earth = 1)">.0553</mass>
        <day units="days">58.65</day>
        <radius units="miles">1516</radius>
        <density units="(Earth = 1)">.983</density>
        <distance units="millions miles">43.4</distance>
    </planet>
    <planet>
        <name>Venus</name>
        <mass units="(Earth = 1)">.815</mass>
        <day units="days">116.75</day>
        <radius units="miles">3716</radius>
        <density units="(Earth = 1)">.943</density>
        <distance units="millions miles">66.8</distance>
    </planet>
    <planet>
        <name>Earth</name>
        <mass units="(Earth = 1)">1</mass>
        <day units="days">1</day>
        <radius units="miles">2107</radius>
        <density units="(Earth = 1)">1</density>
        <distance units="millions miles">128.4</distance>
    </planet>
</planets>