Ticket #539: defaultfilters.py.diff

defaultfilters.py

@@ -245 +245 @@
     for an introduction.
     """
     try:
-        start, finish = arg.split(':')
+        pieces = arg.split(':')
+        if len(pieces) == 2:
+            (start, finish), stride = pieces, None
+        else:
+            start, finish, stride = pieces
     except ValueError: # unpack list of wrong size
         return value # fail silently but nicely
     try:
         if start and finish:
-            return value[int(start):int(finish)]
+            if stride:
+                return value[int(start):int(finish):int(stride)]
+            else:
+                return value[int(start):int(finish)]
         if start:
-            return value[int(start):]
+            if stride:
+                return value[int(start)::int(stride)]
+            else:
+                return value[int(start):]
         if finish:
-            return value[:int(finish)]
+            if stride:
+                return value[:int(finish)]
+            else:
+                return value[:int(finish):int(stride)]
+        if stride:
+            return value[::int(stride)]
     except TypeError:
         pass
     return value