Refactoring: Remove global variables

README.md

@@ -11,18 +11,3 @@ acquaintances using dictionaries and lists.
 - Each person in the group has an age.
 - Each person in the group can have a job.
 - Each person can be connected to others in different ways, such as "friend", "granddaughter", "colleague" etc.
-
-Think about how you want to represent the various types of information and the connections between them.
-
-# Part 1
-Create an example instance, in an editor or a notebook, of a structure for this group:
-- Jill is 26, a biologist and she is Zalika's friend and John's partner.
-- Zalika is 28, an artist, and Jill's friend
-- John is 27, a writer, and Jill's partner.
-- Nash is 34, a chef, John's cousin and Zalika's landlord.
-
-Some things you may wish to consider in your model:
-- Does it allow people who have no job?
-- Does it allow people with no connections?
-- Does it assume that connections are always reciprocal (e.g. if A is B's friend, does B
-automatically consider A a friend too?)

refactoring/initial_global.py

@@ -0,0 +1,60 @@
+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(group, person1, person2):
+    """Remove the connection between two people."""
+    group[person1]["relations"].pop(person2, None)
+    group[person2]["relations"].pop(person1, None)
+
+
+def add_person(group, name, age, job, relations):
+    """Add a new person with the given characteristics to the group."""
+    new_person = {
+        "age": age,
+        "job": job,
+        "relations": relations
+    }
+    group[name] = new_person
+
+if __name__ == "__main__":
+    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"
+        }
+    }
+}
+
+    nash_relations = {
+        "John": "cousin",
+        "Zalika": "landlord"
+    }
+
+    add_person(group, "Nash", 34, "chef", nash_relations)
+
+    forget(group, "Nash", "John")
+
+    assert len(group) == 4, "Group should have 4 members"
+    assert average_age(group) == 28.75, "Average age of the group is incorrect!"
+    assert len(group["Nash"]["relations"]) == 1, "Nash should only have one relation"
+    print("All assertions have passed!")

refactoring/initial_person_class.py

@@ -0,0 +1,52 @@
+class Person:
+    """A class to represent an individual and their connections."""
+
+    def __init__(self, name, age, job):
+        """Create a new Person with the given name, age and job and no connections."""
+        self.name = name
+        self.age = age
+        self.job = job
+        self.connections = dict()
+
+    def add_connection(self, person, relation):
+        """Add a new connection to a person"""
+        if person in self.connections:
+            raise ValueError(f"I already know about {person.name}")
+        self.connections[person] = relation
+
+    def forget(self, person):
+        """Removes any connections to a person"""
+        self.connections.pop(person, None)
+
+
+def average_age(group):
+    """Compute the average age of the group's members."""
+    all_ages = [person.age for person in group]
+    return sum(all_ages) / len(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")
+    jill.add_connection(john, "partner")
+    zalika.add_connection(jill, "friend")
+    john.add_connection(jill, "partner")
+    nash.add_connection(john, "cousin")
+    nash.add_connection(zalika, "landlord")
+
+    # ... then forget Nash and John's connection
+    nash.forget(john)
+    # Then create the group
+    my_group = {jill, zalika, john, nash}
+
+    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(nash.connections) == 1, "Nash should only have one relation "
+    print("All assertions have passed!")

refactoring/initial_two_classes.py

@@ -0,0 +1,85 @@
+class Person:
+    """A class to represent an individual."""
+
+    def __init__(self, name, age, job):
+        """Create a new Person with the given name, age and job."""
+        self.name = name
+        self.age = age
+        self.job = job
+
+
+class Group:
+    """A class that represents a group of individuals and their connections."""
+
+    def __init__(self):
+        """Create an empty group."""
+        self.members = []
+        self.connections = {}
+
+    def size(self):
+        """Return how many people are in the group."""
+        return len(self.members)
+
+    def contains(self, name):
+        """Check whether the group contains a person with the given name.
+        Useful to throw errors if we try to add a person who already exists or forget someone.
+        """
+        return any(member.name == name for member in self.members)
+
+    def add_person(self, name, age, job):
+        """Add a new person with the given characteristics to the group."""
+        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"""
+        return len(self.connections[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
+        """
+        if name1 not in self.connections:
+            self.connections[name1] = []
+        if name2 not in self.connections:
+            self.connections[name2] = []
+
+        self.connections[name1].append({name2: relation})
+
+        if reciprocal:
+            self.connections[name2].append({name1: relation})       
+
+    def forget(self, name1, name2):
+        """Remove the connection between two people."""
+        if name1 in self.connections:
+            self.connections[name1] = [conn for conn in self.connections[name1] if name2 not in conn]
+        if name2 in self.connections:
+            self.connections[name2] = [conn for conn in self.connections[name2] if name1 not in conn]
+
+    def average_age(self):
+        """Compute the average age of the group's members."""
+        all_ages = [person.age for person in self.members]
+        return sum(all_ages) / self.size()
+
+
+if __name__ == "__main__":
+    # Start with an empty group...
+    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")
+    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"
+    print("All assertions have passed!")