Score Filer takes the scores of a test and returns the Average, Lowest, and Highest score(s) of the test.

ScoreFiler.py

# Input student records from a file and return a list of records:
def read(fileName):
    listOfStudents = [];
    inFile = open(fileName, 'rU'); # read in "universal end-of-line" mode
    for line in inFile:
        # Strip unnecessary '\n' from right end:
        line = line.rstrip('\n');
        student = line.split(',');
        # student = ['last-name', 'first-name', 'score']
        listOfStudents.append(student);
    inFile.close();
    return listOfStudents;

# Output a list of student records into a file :
def write(listOfStudents, fileName):
    outFile = open(fileName, 'w');
    for student in listOfStudents:
        string = ','.join(student);
        print >> outFile, string;
    outFile.close();

# Input student records, add letter grades, and output records:
def scores():
    inFileName = raw_input('Enter name of file to read from: ');
    listOfStudents = read(inFileName);
    listOfStudents.sort();
    for student in listOfStudents:
        # student = ['last-name', 'first-name', 'score']
        score = int(student[2]); # Convert score string into int score
        student.append(str(theGrade(score)));
    outFileName = raw_input('Enter name of file to write into: ');
    write(listOfStudents, outFileName);
    print 'Students processed:', len(listOfStudents);

# Transform score into a letter grade:
def theGrade(score):
    if (score < 60):    grade = 'F';
    elif (score < 70):  grade = 'D';
    elif (score < 80):  grade = 'C';
    elif (score < 90):  grade = 'B';
    else:               grade = 'A';
    return grade;

# Input student records from a file; determine and output min, max, and average scores:
def summary():
    inFileName = raw_input('Enter name of file to read from: ');
    listOfStudents = read(inFileName);
    counter = len(listOfStudents);
    print 'Students processed:', counter;
    if (counter > 0):
        total = 0;
        firstStudent = listOfStudents[0];
        firstScore = firstStudent[2];
        minScore = int(firstScore);
        maxScore = int(firstScore);
        for student in listOfStudents:
            score = int(student[2]);
            total = total + score;
            if (score < minScore): minScore = score;
            if (maxScore < score): maxScore = score;
        print 'Average score:', round(total / float(counter));
        print 'Lowest score:', minScore;
        print 'Highest score:', maxScore;