Add final_time accessor

This returns the final time slice of a dataset or dataarray, whether the data contains multiple time slices or not. This is helpful when working with multiple simulations, some of which may have only been run for one timestep for developer reasons.

Author: mikekryjak

xbout/boutdataarray.py

@@ -1169,3 +1169,13 @@ def as_cherab_emitter(
             cylinder_rmax=cyliner_rmax,
             step=step,
         )
+        
+    def final_time(self):
+        """
+        Returns the final time in the Dataset whether
+        it contains a time dimension or not.
+        """
+        if "t" in self.data.sizes:
+            return self.data.isel(t=-1)
+        else:
+            return self.data

xbout/boutdataset.py

@@ -33,7 +33,6 @@
     _split_into_restarts,
 )
 
-
 @xr.register_dataset_accessor("bout")
 class BoutDatasetAccessor:
     """
@@ -1355,7 +1354,16 @@ def with_cherab_grid(self):
         from .cherab import grid
 
         return grid.ds_with_cherab_grid(self.data)
-
+    
+    def final_time(self):
+        """
+        Returns the final time in the Dataset whether
+        it contains a time dimension or not.
+        """
+        if "t" in self.data.sizes:
+            return self.data.isel(t=-1)
+        else:
+            return self.data
 
 def _find_major_vars(data):
     """