floor()

Description

floor() returns the largest integer that is less than or equal to its argument. In plain terms, it rounds a number down toward negative infinity. For positive numbers this truncates the decimal part; for negative numbers this rounds away from zero.

The argument is first converted to a number using the same rules as number(). If the argument is already an integer, it is returned unchanged. If the argument is NaN or infinite, the same special value is returned.

Common uses include computing page numbers, calculating array indices from fractional results, and trimming calculated dimensions to integer pixel values.

Parameters

Return value

xs:double — the largest integer value less than or equal to the argument.

Examples

Compute page count from item count

Input XML:

<?xml version="1.0" encoding="UTF-8"?>
<catalog>
  <item>A</item>
  <item>B</item>
  <item>C</item>
  <item>D</item>
  <item>E</item>
</catalog>

Stylesheet:

<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
  <xsl:output method="xml" indent="yes"/>

  <xsl:variable name="pageSize" select="2"/>

  <xsl:template match="/catalog">
    <xsl:variable name="total" select="count(item)"/>
    <pagination>
      <total-items><xsl:value-of select="$total"/></total-items>
      <full-pages><xsl:value-of select="floor($total div $pageSize)"/></full-pages>
    </pagination>
  </xsl:template>
</xsl:stylesheet>

Output:

<pagination>
  <total-items>5</total-items>
  <full-pages>2</full-pages>
</pagination>

Floor of positive and negative numbers

Input XML:

<?xml version="1.0" encoding="UTF-8"?>
<values>
  <v>3.7</v>
  <v>-3.7</v>
  <v>5.0</v>
</values>

Stylesheet:

<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
  <xsl:output method="xml" indent="yes"/>

  <xsl:template match="/values">
    <results>
      <xsl:for-each select="v">
        <floor of="{.}"><xsl:value-of select="floor(.)"/></floor>
      </xsl:for-each>
    </results>
  </xsl:template>
</xsl:stylesheet>

Output:

<results>
  <floor of="3.7">3</floor>
  <floor of="-3.7">-4</floor>
  <floor of="5.0">5</floor>
</results>

Notes

• floor(-3.7) returns -4, not -3. Rounding is always toward negative infinity, not toward zero.
• If the argument is NaN, floor() returns NaN.
• If the argument is Infinity or -Infinity, the same infinity is returned unchanged.
• floor() returns a double type in XPath 1.0, so the output may include a trailing .0 on some processors when serialised. Use round() or integer arithmetic if you need a guaranteed integer format.
• For rounding toward zero (truncation), there is no dedicated XPath 1.0 function; the common workaround is floor($n) for positive numbers or ceiling($n) for negative ones.

See also

• ceiling()
• round()
• number()