helpers.py

from sympy.functions import re
import re

# Official grade point equivalencies from the Swarthmore College registrar
GRADE_POINT_EQUIVS = {'A+': 4.0,
                      'A' : 4.0,
                      'A-': 3.67,
                      'B+': 3.33,
                      'B' : 3.0,
                      'B-': 2.67,
                      'C+': 2.33,
                      'C' : 2.0,
                      'C-': 1.67,
                      'D+': 1.33,
                      'D' : 1.0,
                      'D-': 0.67,
                      'F' : 0.0,
                      }

def grade_point_equiv(grade_str):
    if grade_str in GRADE_POINT_EQUIVS:
        # Grade is already in letter format
        return GRADE_POINT_EQUIVS[grade_str]
    elif re.match(r'[0-4].[0-9]{1,2}$', grade_str):
        # Grade is formatted as a grade point float (for Bryn Mawr and 
        # Haverford classes)
        return float(grade_str)
    else:
        # Course grade is not in valid format (e.g., 1, CR, NC) and
        # doesn't affect GPA
        return None

def parse_grades(raw_grades):
    """Convert from a string of grades to a structured dict.

    Args:
        raw_grades: A string containing the user's raw grades copied and pasted
            from MySwarthmore (hopefully)
    Returns:
        A list of dicts, one per course found while parsing raw_grades, with
        the fields: ['affects_gpa', 'course', 'title', 'credits_earned', 'grade',
        'division', 'instructor']
    """
    lines = raw_grades.split("\n")

    # Remove term header lines
    course_exp = re.compile("[A-Z]{4}\s\d{3}") # Course regex
    def is_course_line(line): 
        return line.strip() and \
               course_exp.search(line)
    courses = list(filter(is_course_line, lines))

    # Convert each course row to a dict
    course_list = []
    for course in courses:
        course_info = [field.strip() for field in course.split("\t")] # Split up fields of row
        course_info = course_info[1:] # Chop off the tab or the term
        course_info.append(True) # Assume course affects GPA
        course_fields = ['course', 
                         'title', 
                         'credits_attemped',
                         'credits_earned',
                         'grade', 
                         'division', 
                         'instructor',
                         'affects_gpa']
        if len(course_info) == len(course_fields):
            course_dict = dict(zip(course_fields, course_info))

            if grade_point_equiv(course_dict['grade']) is None:
                course_dict['affects_gpa'] = False
            course_list.append(course_dict)

    return course_list