XPath Selector Join Elements - xpath

Question

I need to use XPath to select and return the values of elements "Longitude" and "Latitude" in the below XML.
<LocationsList>
<Locations>
<Id>31dbwlph0yi--1</Id>
<Latitude>45.352304</Latitude>
<Longitude>-75.724945</Longitude>
</Locations>
<Locations>
<Id>600001-0-0--1</Id>
<Latitude>45.33142</Latitude>
<Longitude>-79.96399</Longitude>
</Locations>
</LocationsList>
Here's what I need my XPath to return (where one list item returns both Latitude and Longitude):
1. 45.352304 -75.724945
2. 45.33142 -79.96399
Unfortunately, I'm having trouble. Here's what I've tried...
XPath LocationsList/Locations returns:
1. 31dbwlph0yi--1 45.352304 -75.724945
2. 600001-0-0--1 HWY 400 45.33142 -79.96399
XPath LocationsList/Locations/(Latitude | Longitude) returns:
1. 45.35304
2. -75.724945
3. 45.33142
4. -79.96399
XPath LocationsList/Locations/concat(Latitude, " ", Longitude) returns a string:
Non-standard output:
45.352304 -75.724945
45.33142 -79.96399

Answer 1

Prior to XPath 3.1, there's no array data type in the data model. The best you could do is return a sequence, but NB there's no such thing as a sequence of sequences; a sequence is necessarily a flat list. Let's see how this works with your sample data:
<LocationsList>
<Locations>
<Id>31dbwlph0yi--1</Id>
<Latitude>45.352304</Latitude>
<Longitude>-75.724945</Longitude>
</Locations>
<Locations>
<Id>600001-0-0--1</Id>
<Latitude>45.33142</Latitude>
<Longitude>-79.96399</Longitude>
</Locations>
</LocationsList>
Take this one of your expressions:
/LocationsList/Locations/concat(Latitude, " ", Longitude)
It produces a sequence of 2 strings which each contain a latitude and a longitude value, separated by a space:
("45.352304 -75.724945", "45.33142 -79.96399")
Or you could use an expression like this to select a sequence of either Latitude or Longitude elements and convert them to numbers:
LocationsList/Locations/(Latitude | Longitude)/number(.)
That returns a sequence of 4 numbers, which are alternately latitude and longitude values
(45.352304,-75.724945,45.33142,-79.96399)
Finally, in XPath 3.1 you have support for an array datatype, so you can iterate over the sequence of Locations and construct an array from each one, and return a sequence of arrays:
for $location in
/LocationsList/Locations
return
[number($location/Latitude), number($location/Longitude)]
The result is this sequence of arrays, each containing 2 numbers:
([45.352304,-75.724945], [45.33142,-79.96399])
Or if you want to get fancy you could return an array of arrays:
fold-left(
for $location in
/LocationsList/Locations
return
[number($location/Latitude), number($location/Longitude)],
[],
function($array, $location) {
Q{http://www.w3.org/2005/xpath-functions/array}append($array, $location)
}
)
... giving:
[[45.352304,-75.724945],[45.33142,-79.96399]]