XQuery

Finding the Length of a String

The length of a string can be determined using the string-length function. It accepts a single string and returns its length as an integer. Whitespace is significant, so leading and trailing whitespace characters are counted. Table 17-5 shows some examples.

USEFUL FUNCTION: set-string-to-length

The set-string-to-length function, shown here, pads a string to a desired length:

declare namespace functx = "http://www.functx.com";
declare function functx:set-string-to-length
($stringToPad as xs:string?, $padChar as xs:string,
 $length as xs:integer) as xs:string
 {
   substring(
     string-join (($stringToPad, for $i in (1 to $length) return $padChar),"")
    ,1,$length)
 };

The function accepts as arguments a string, a character to pad the string with, and the desired length of the string. For example, you might call this function with:

functx:set-string-to-length("abc", "*", 7)

which returns abc****. This function truncates $stringToPad if it is longer than $length.

Table 17-5. Examples of the string-length function

Example	Return value
string-length("query")	5
string-length(" query ")	9
string-length(normalize-space(" query "))	5
string-length("")	0
string-length(" ")	1