Add example solutions for refactoring

refactoring/initial_global.py

@@ -1,16 +1,16 @@
-def average_age():
+def average_age(group):
     """Compute the average age of the group's members."""
     all_ages = [person["age"] for person in group.values()]
     return sum(all_ages) / len(group)
 
 
-def forget(person1, person2):
+def forget(group, person1, person2):
     """Remove the connection between two people."""
     group[person1]["relations"].pop(person2, None)
     group[person2]["relations"].pop(person1, None)
 
 
-def add_person(name, age, job, relations):
+def add_person(group, name, age, job, relations):
     """Add a new person with the given characteristics to the group."""
     new_person = {
         "age": age,
@@ -20,42 +20,44 @@ def add_person(name, age, job, relations):
     group[name] = new_person
 
 
-group = {
-    "Jill": {
-        "age": 26,
-        "job": "biologist",
-        "relations": {
-            "Zalika": "friend",
-            "John": "partner"
-        }
-    },
-    "Zalika": {
-        "age": 28,
-        "job": "artist",
-        "relations": {
-            "Jill": "friend",
-        }
-    },
-    "John": {
-        "age": 27,
-        "job": "writer",
-        "relations": {
-            "Jill": "partner"
-        }
+def add_nash(group):
+    """Add nash to the group."""
+    nash_relations = {
+        "John": "cousin",
+        "Zalika": "landlord"
     }
-}
-
-nash_relations = {
-    "John": "cousin",
-    "Zalika": "landlord"
-}
+    add_person(group, "Nash", 34, "chef", nash_relations)
 
-add_person("Nash", 34, "chef", nash_relations)
-
-forget("Nash", "John")
 
 if __name__ == "__main__":
-    assert len(group) == 4, "Group should have 4 members"
-    assert average_age() == 28.75, "Average age of the group is incorrect!"
-    assert len(group["Nash"]["relations"]) == 1, "Nash should only have one relation"
+    my_group = {
+        "Jill": {
+            "age": 26,
+            "job": "biologist",
+            "relations": {
+                "Zalika": "friend",
+                "John": "partner"
+            }
+        },
+        "Zalika": {
+            "age": 28,
+            "job": "artist",
+            "relations": {
+                "Jill": "friend"
+            }
+        },
+        "John": {
+            "age": 27,
+            "job": "writer",
+            "relations": {
+                "Jill": "partner"
+            }
+        }
+    }
+    add_nash(my_group)
+    forget(my_group, "Nash", "John")
+
+    assert len(my_group) == 4, "Group should have 4 members"
+    assert average_age(my_group) == 28.75, "Average age of the group is incorrect!"
+    assert len(my_group["Nash"]["relations"]) == 1, "Nash should only have one relation"
     print("All assertions have passed!")

refactoring/initial_person_class.py

@@ -16,7 +16,9 @@ def add_connection(self, person, relation):
 
     def forget(self, person):
         """Removes any connections to a person"""
-        pass
+        if person not in self.connections:
+            raise ValueError(f"I don't know about {person.name}")
+        self.connections.pop(person)
 
 
 def average_age(group):
@@ -28,11 +30,17 @@ def average_age(group):
 if __name__ == "__main__":
     # ...then create the group members one by one...
     jill = Person("Jill", 26, "biologist")
-
+    zalika = Person("Zalika", 28, "artist")
+    john = Person("John", 27, "writer")
+    nash = Person("Nash", 34, "chef")
     # ...then add the connections one by one...
-    # Note: this will fail from here if the person objects aren't created
     jill.add_connection(zalika, "friend")
-
+    zalika.add_connection(jill, "friend")
+    jill.add_connection(john, "partner")
+    john.add_connection(john, "partner")
+    nash.add_connection(john, "cousin")
+    john.add_connection(nash, "cousin")
+    nash.add_connection(zalika, "Landlord")
     # ... then forget Nash and John's connection
     nash.forget(john)
     # Then create the group

refactoring/initial_two_classes.py

@@ -18,7 +18,7 @@ def __init__(self):
 
     def size(self):
         """Return how many people are in the group."""
-        pass
+        return len(self.members)
 
     def contains(self, name):
         """Check whether the group contains a person with the given name.
@@ -28,21 +28,40 @@ def contains(self, name):
 
     def add_person(self, name, age, job):
         """Add a new person with the given characteristics to the group."""
+        if self.contains(name):
+            raise ValueError(f"I already know about {name}.")
         self.members.append(Person(name, age, job))
 
     def number_of_connections(self, name):
         """Find the number of connections that a person in the group has"""
-        pass
+        if not self.contains(name):
+            raise ValueError(f"I don't know about {name}.")
+        return sum(1 for (first, second) in self.connections if first == name)
 
     def connect(self, name1, name2, relation, reciprocal=True):
         """Connect two given people in a particular way.
         Optional reciprocal: If true, will add the relationship from name2 to name 1 as well
         """
-        pass
+        if not self.contains(name1):
+            raise ValueError(f"I don't know who {name1} is.")
+        if not self.contains(name2):
+            raise ValueError(f"I don't know who {name2} is.")
+        if (name1, name2) in self.connections:
+            raise ValueError(f"{name1} already knows {name2} as a "
+                             f"{self.connections[(name1, name2)]}")
+        self.connections[(name1, name2)] = relation
+        if reciprocal:
+            self.connections[(name2, name1)] = relation
 
     def forget(self, name1, name2):
         """Remove the connection between two people."""
-        pass
+        if not self.contains(name1):
+            raise ValueError(f"I don't know who {name1} is.")
+        if not self.contains(name2):
+            raise ValueError(f"I don't know who {name2} is.")
+        if (name1, name2) not in self.connections:
+            raise ValueError(f"{name1} does not know {name2} yet.")
+        self.connections.pop((name1, name2))
 
     def average_age(self):
         """Compute the average age of the group's members."""
@@ -55,11 +74,18 @@ def average_age(self):
     my_group = Group()
     # ...then add the group members one by one...
     my_group.add_person("Jill", 26, "biologist")
+    my_group.add_person("Zalika", 28, "artist")
+    my_group.add_person("John", 27, "writer")
+    my_group.add_person("Nash", 34, "chef")
     # ...then their connections
     my_group.connect("Jill", "Zalika", "friend")
+    my_group.connect("Jill", "John", "partner")
+    my_group.connect("Nash", "John", "cousin", reciprocal=False)
+    my_group.connect("Nash", "Zalika", "landlord", reciprocal=False)
     # ... then forget Nash and John's connection
     my_group.forget("Nash", "John")
 
+    assert my_group.contains("John"), "John should be in the group"
     assert my_group.size() == 4, "Group should have 4 members"
     assert my_group.average_age() == 28.75, "Average age of the group is incorrect!"
     assert my_group.number_of_connections("Nash") == 1, "Nash should only have one relation"