substring() Function — Returns a portion of a given string. The second and third arguments determine what portion of the string is returned. The second argument specifies the position of the first character of the substring, and the optional third argument specifies how many characters should be returned.
substring() function takes a string and one or two numbers as arguments. The string is the string from which the substring will be extracted. The second argument is used as the starting position of the returned substring, and the optional third argument specifies how many characters are returned.
With two arguments (a string and a starting position), the
substring() function returns all characters in the string, starting with the starting position. Be aware that the first character in an XPath string is at position 1, not 0.
With three arguments (a string, a starting position, and a length), the
substring() function returns all characters in the string whose position is greater than or equal to the starting position and whose position is less than or equal to the starting position plus the length.
Normally, the arguments to the
substring() function are integers, although they may be more complicated expressions. See the “Example” section that follows for some unusual cases.
XPath section 4.2, String Functions.
We’ll use this XML document to demonstrate how the
substring() function works:
<?xml version="1.0"?> ...