Creating XPath Expressions
The XPath Expression Editor helps you build valid XPath Expressions, providing the available functions and operators for you to use.
In this example, the concat function is selected, which automatically starts building the expression in the Expression field. This expression updates and grows as you select from the lists of functions and operators available to you.
To cycle through the variables, XPath functions, and XPath operations available to you, press Ctl+Space. Type the dollar sign ($) in the editor to display a list of variables.
See XPath Functions and Operators for a function reference and list of operators with their descriptions. The Process Server defaults to string comparisons when you use relational operators in your expressions. When you compare numbers (floats and doubles, in particular), you should explicitly specify that you want a number comparison. You can do this by converting the operands with the number() function. For example, number(var1)= number(var2) instead of var1>= var2.
More information