simple_course_grading_good_code

#!/usr/bin/env python
marks = [75, 45, 89, 55, 65, 50, 72, 70, 60, 80, 95,
    34, 83, 71, 65, 53, 58, 79, 85, 21, 67, 94, 77]

def grade_single_score(score_mark):
    grades = [['U', 0,  49],
         ['D',  50, 59],
         ['C',  60, 69],
         ['B',  70, 79],
         ['A',  80, 89],
         ['A*', 90, 100]]
    for grade in grades:
        if grade[1] <= score_mark <= grade[2]:
            return grade[0]
    return 'N/A'

def grade_and_print_scores(score_list):
    for idx, score in enumerate(score_list):
        grade = grade_single_score(score)
        print("Mark [%d] - %d - %s" % (idx, score, grade))

def compare_tuple_by_grade(lhs, rhs):
    if lhs[0].endswith('*'):
    return -1
    return cmp(lhs, rhs)

def print_grade_distribution(score_list):
    grades_distr = {}
    for score in score_list:
    grade = grade_single_score(score)
    if not grades_distr.has_key(grade):
        grades_distr[grade] = 1
    else:
        grades_distr[grade] = grades_distr[grade] + 1

    for grade, frequency in sorted(grades_distr.items(), compare_tuple_by_grade):
    print("Grade [%s] - %i" % (grade, frequency))

grade_and_print_scores(marks)
print("--------------------")
print_grade_distribution(marks)