Merge pull request #46 from aollier/shipdict-ref

Shipdict ref - remove duplicates

data/shipdict.py

@@ -64,6 +64,17 @@ def __repr__(self):
         only used when merger.py is run in verbose mode
         """
         return f"<{self.lat_str()} {self.lon_str()} @ {self.timestamp}>"
+
+    # required to be stored in a set
+    # see https://docs.python.org/3/reference/datamodel.html#object.__hash__
+    def __hash__(self):
+        return hash((self.latitude, self.longitude, self.timestamp))
+
+    # a hashable shall override this special method
+    def __eq__(self, other):
+        return (self.latitude == other.latitude
+                and self.longitude == other.longitude
+                and self.timestamp == other.timestamp)
 # @END@
 
 # @BEG@ name=shipdict more=suite
@@ -96,9 +107,11 @@ def add_position(self, position):
 
     def sort_positions(self):
         """
-        sort list of positions by chronological order
+        sort of positions made unique thanks to the set by chronological order
+        for this to work, a Position must be hashable
         """
-        self.positions.sort(key=lambda position: position.timestamp)
+        self.positions = sorted(set(self.positions),
+                                key=lambda position: position.timestamp)
 # @END@
 
 # @BEG@ name=shipdict more=suite
@@ -117,7 +130,8 @@ def __init__(self):
     def __repr__(self):
         return f"<ShipDict instance with {len(self)} ships>"
 
-    def is_abbreviated(self, chunk):
+    @staticmethod
+    def is_abbreviated(chunk):
         """
         depending on the size of the incoming data chunk,
         guess if it is an abbreviated or extended data
@@ -159,7 +173,12 @@ def add_chunk(self, chunk):
         based on the result of is_abbreviated(),
         gets sent to add_extended or add_abbreviated
         """
-        if self.is_abbreviated(chunk):
+        # here we retrieve the static method through the class
+        # this form outlines the fact that we're calling a static method
+        # note that
+        # self.is_abbreviated(chunk)
+        # would work fine just as well
+        if ShipDict.is_abbreviated(chunk):
             self.add_abbreviated(chunk)
         else:
             self.add_extended(chunk)

w6/w6-s8-x1-classes-merger.md

@@ -261,10 +261,9 @@ Comparing ALL_SHIPS.kml and ALL_SHIPS.kml.ref -> OK
 À noter que dans le mode bavard toutes les positions sont listées dans le résumé au format texte, ce qui le rend beaucoup plus bavard comme vous pouvez le voir en inspectant la taille des deux fichiers de référence :
 
 ```python
-$ ls -l ALL_SHIPS*txt.ref v2.0
--rw-r--r--  1 parmentelat  staff  1438681 Dec  4 16:20 ALL_SHIPS-v.txt.ref
--rw-r--r--  1 parmentelat  staff    15331 Dec  4 16:20 ALL_SHIPS.txt.ref
--rw-r--r--  1 parmentelat  staff        0 Dec  4 16:21 v2.0
+$ ls -l ALL_SHIPS*txt.ref
+-rw-r--r--  1 parmentelat  staff  1433373 Dec  4 16:20 ALL_SHIPS-v.txt.ref
+-rw-r--r--  1 parmentelat  staff    15273 Dec  4 16:20 ALL_SHIPS.txt.ref
 ```
 
 +++