normalize-space() returns the argument string with white space normalized by stripping leading and trailing whitespace and replacing sequences of whitespace characters by a single space. : normalize space « XSLT stylesheet « XML Tutorial

1. XML Tutorial
2. XSLT stylesheet
3. normalize space

File: Data.xml
<?xml version="1.0" encoding="utf-8"?>
<paragraph>
  <text>Normalized text</text>
  <text>Sequences   of      whitespace characters</text>
  <text>    Leading and trailing whitespace.    </text>
</P>
File: Transform.xslt

<?xml version="1.0" encoding="utf-8"?>
<xsl:stylesheet
      version="1.0"
      xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
    <xsl:template match="/">
      <TABLE>
        <xsl:for-each select="//text">
          <TR>
            <TH colspan="4">
              <xsl:value-of select="."/>
            </TH>
          </TR>
          <TR>
            <TD>Starting length:</TD>
            <TD>
              <xsl:value-of select="string-length(.)"/>
            </TD>
            <TD>Normalized length:</TD>
            <TD>
              <xsl:value-of select="string-length(normalize-space(.))"/>
            </TD>
          </TR>
        </xsl:for-each>
      </TABLE>
    </xsl:template>
</xsl:stylesheet>

Output:

<?xml version="1.0" encoding="UTF-8"?><TABLE><TR><TH colspan="4">Normalized text</TH></TR><TR><TD>Starting length:</TD><TD>15</TD><TD>Normalized length:</TD><TD>15</TD></TR><TR><TH colspan="4">Sequences   of      whitespace characters</TH></TR><TR><TD>Starting length:</TD><TD>41</TD><TD>Normalized length:</TD><TD>34</TD></TR><TR><TH colspan="4">    Leading and trailing whitespace.    </TH></TR><TR><TD>Starting length:</TD><TD>40</TD><TD>Normalized length:</TD><TD>32</TD></TR></TABLE>