Product: Mapping Manager

Article Link: http://help.truecommerce.com/en/articles/10002618-xpath-predicate-selection-by-instance-ordering

Often when writing an xPath you may need to filter the results of your selection down to a specific result based on its order in the XML (sometimes called an instance). Whether you need to select the first, second, or last element.

You can do this by utilizing either a static selector or by calling one of the handy functions that exist to check against a particular order.

In this example we have an Advance Ship Notice (856) that is formatted in the SOPI (Shipment, Order, Pack, Item) structure.

You can select a particular element based on its placement relative to its other siblings utilizing the Instance Selection predicate. Defining which specific element you want is useful for limiting results, as well as grabbing something from a specific spot.

You can use predicate brackets [ ] to define which instance you would like to select.

Often when you write an xPath you may return multiple results - however to write the value to a field, Transaction Manager needs to have only a single value returned in order to properly write.

You can do this by hard-coding a static number such as [1] or [5] to select that specific number.

Let's say your Advance Ship Notice (856) has multiple UCC-128s on it. You need to pull the Master Tracking number, but it's not defined on the XML in its own spot. You know that the first Pack always contains the master UCC-128 on it. You can select it, by hard-coding a [1] to your predicate.

Perhaps you need to select the 2nd item within the 1st package specifically? Well you can do so by first selecting the 1st package, and then by selecting the 2nd item of that package.

If we wish to select the very last package in an unknown amount of packages, we can do so by using the last() predicate.

In addition to hard-coding the instance, you can check whether or not the Node is Even or Even by utilizing the position() function which allows us to compare its position, along with the mod function to determine if the function is odd or even.

10/16/2024