In [12]:
with open("grades.txt") as f:
    data = f.read()
print(data)
records = data.split('\n')
print(records)

Jones:CSC 1301:4:A
Jones:CSC 1302:4:A
Jones:CSC 2720:3:B
Smith:CSC 1301:4:B
Smith:CSC 1302:4:B
Smith:CSC 2720:3:A
Blake:CSC 1301:4:B
Blake:CSC 1301:4:B
Blake:CSC 1301:4:B
Blake:CSC 1301:4:B
['Jones:CSC 1301:4:A', 'Jones:CSC 1302:4:A', 'Jones:CSC 2720:3:B', 'Smith:CSC 1301:4:B', 'Smith:CSC 1302:4:B', 'Smith:CSC 2720:3:A', 'Blake:CSC 1301:4:B', 'Blake:CSC 1301:4:B', 'Blake:CSC 1301:4:B', 'Blake:CSC 1301:4:B']
In [4]:
grades = {}
for record in records:
    r = record.split(':')
    #print(r)
    name = r[0]
    cno = r[1]
    credits = int(r[2])
    grade = r[3]
    if name not in grades:
        grades[name] = [(cno,credits,grade)]
    else:
        #grades[name].append((cno,credits,grade))
        grades[name] = grades[name] + [(cno,credits,grade)]
print(grades)

{'Jones': [('CSC 1301', 4, 'A'), ('CSC 1302', 4, 'A'), ('CSC 2720', 3, 'B')], 'Smith': [('CSC 1301', 4, 'B'), ('CSC 1302', 4, 'B'), ('CSC 2720', 3, 'A')], 'Blake': [('CSC 1301', 4, 'B'), ('CSC 1301', 4, 'B'), ('CSC 1301', 4, 'B'), ('CSC 1301', 4, 'B')]}
In [13]:
def gpa(name,grades):
    numeric_grades = {'A':4, 'B':3, 'C':2, 'D':1, 'F':0}
    if name in grades:
        courses = grades[name]
        result = 0.0
        ncredits = 0
        for course in courses:
            crs = course[1]
            grade = numeric_grades[course[2]]
            ncredits = ncredits + course[1]
            result = result + grade*crs
        return result/ncredits
    else:
        return None
In [19]:
print(gpa('Jones',grades))

3.727272727272727
In [20]:
print(gpa('Smith',grades))

3.272727272727273
In [21]:
print(gpa('Blake',grades))

3.0
In [22]:
print(gpa('Sunderraman',grades))

None
In [ ]: