More XPath expressions

Example 39

XPath expressions

A field value reference to a field in the third instance of block1:

/data/message/block1[3]/field1

A relative path to the position_x field:

./position_x

A specific value of a variable:

$section[.="Section3"]

The first three instances of a block:

/data/message/block1[position()<=3]

The last three instances of a block:

/data/message/block1[position() > last()-3]

The value of the current array index when repeating for example a table row:

$x[@index = current()/@index]

Current context, with the condition that variable has specific value:

self::*[$section=’Section3’]

Current context, with the condition that the field is defined and has a non-blank value:

self::*[string(field)]

 

Example 40

Return the value of $color_red variable if the value is negative.

$color_red[current()/value < 0]

 

Example 41

Returning static data, in this case a string representing color red, for negative values

The string is returned for 1 div (value < 0) = 1. This is because the second argument of substring() is the start position of the returned string. 1 div (value < 0) = 1 if (value < 0) is true since true = 1. If (value>=0) is false, then the start position is 1 div 0 which is infinity. In this case, there is no start position of the string and an empty string is returned, which means no modification on the color property.

substring(’RGB(255,0,0)’, 1 div (value < 0))