387 lines
17 KiB
Python
387 lines
17 KiB
Python
import abc
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import inspect
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import logging
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import random
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import sys
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from collections import namedtuple
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log = logging.getLogger("edx.courseware")
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# This is a tuple for holding scores, either from problems or sections.
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# Section either indicates the name of the problem or the name of the section
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Score = namedtuple("Score", "earned possible graded section")
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def aggregate_scores(scores, section_name="summary"):
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"""
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scores: A list of Score objects
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returns: A tuple (all_total, graded_total).
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all_total: A Score representing the total score summed over all input scores
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graded_total: A Score representing the score summed over all graded input scores
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"""
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total_correct_graded = sum(score.earned for score in scores if score.graded)
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total_possible_graded = sum(score.possible for score in scores if score.graded)
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total_correct = sum(score.earned for score in scores)
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total_possible = sum(score.possible for score in scores)
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#regardless of whether or not it is graded
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all_total = Score(total_correct,
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total_possible,
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False,
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section_name)
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#selecting only graded things
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graded_total = Score(total_correct_graded,
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total_possible_graded,
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True,
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section_name)
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return all_total, graded_total
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def invalid_args(func, argdict):
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"""
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Given a function and a dictionary of arguments, returns a set of arguments
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from argdict that aren't accepted by func
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"""
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args, _, keywords, _ = inspect.getargspec(func)
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if keywords:
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return set() # All accepted
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return set(argdict) - set(args)
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def grader_from_conf(conf):
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"""
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This creates a CourseGrader from a configuration (such as in course_settings.py).
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The conf can simply be an instance of CourseGrader, in which case no work is done.
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More commonly, the conf is a list of dictionaries. A WeightedSubsectionsGrader
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with AssignmentFormatGrader's or SingleSectionGrader's as subsections will be
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generated. Every dictionary should contain the parameters for making either a
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AssignmentFormatGrader or SingleSectionGrader, in addition to a 'weight' key.
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"""
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if isinstance(conf, CourseGrader):
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return conf
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subgraders = []
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for subgraderconf in conf:
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subgraderconf = subgraderconf.copy()
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weight = subgraderconf.pop("weight", 0)
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# NOTE: 'name' used to exist in SingleSectionGrader. We are deprecating SingleSectionGrader
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# and converting everything into an AssignmentFormatGrader by adding 'min_count' and
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# 'drop_count'. AssignmentFormatGrader does not expect 'name', so if it appears
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# in bad_args, go ahead remove it (this causes no errors). Eventually, SingleSectionGrader
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# should be completely removed.
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name = 'name'
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try:
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if 'min_count' in subgraderconf:
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#This is an AssignmentFormatGrader
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subgrader_class = AssignmentFormatGrader
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elif name in subgraderconf:
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#This is an SingleSectionGrader
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subgrader_class = SingleSectionGrader
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else:
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raise ValueError("Configuration has no appropriate grader class.")
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bad_args = invalid_args(subgrader_class.__init__, subgraderconf)
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# See note above concerning 'name'.
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if bad_args.issuperset({name}):
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bad_args = bad_args - {name}
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del subgraderconf[name]
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if len(bad_args) > 0:
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log.warning("Invalid arguments for a subgrader: %s", bad_args)
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for key in bad_args:
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del subgraderconf[key]
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subgrader = subgrader_class(**subgraderconf)
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subgraders.append((subgrader, subgrader.category, weight))
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except (TypeError, ValueError) as error:
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# Add info and re-raise
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msg = ("Unable to parse grader configuration:\n " +
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str(subgraderconf) +
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"\n Error was:\n " + str(error))
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raise ValueError(msg), None, sys.exc_info()[2]
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return WeightedSubsectionsGrader(subgraders)
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class CourseGrader(object):
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"""
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A course grader takes the totaled scores for each graded section (that a student has
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started) in the course. From these scores, the grader calculates an overall percentage
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grade. The grader should also generate information about how that score was calculated,
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to be displayed in graphs or charts.
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A grader has one required method, grade(), which is passed a grade_sheet. The grade_sheet
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contains scores for all graded section that the student has started. If a student has
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a score of 0 for that section, it may be missing from the grade_sheet. The grade_sheet
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is keyed by section format. Each value is a list of Score namedtuples for each section
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that has the matching section format.
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The grader outputs a dictionary with the following keys:
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- percent: Contains a float value, which is the final percentage score for the student.
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- section_breakdown: This is a list of dictionaries which provide details on sections
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that were graded. These are used for display in a graph or chart. The format for a
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section_breakdown dictionary is explained below.
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- grade_breakdown: This is a list of dictionaries which provide details on the contributions
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of the final percentage grade. This is a higher level breakdown, for when the grade is constructed
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of a few very large sections (such as Homeworks, Labs, a Midterm, and a Final). The format for
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a grade_breakdown is explained below. This section is optional.
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A dictionary in the section_breakdown list has the following keys:
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percent: A float percentage for the section.
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label: A short string identifying the section. Preferably fixed-length. E.g. "HW 3".
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detail: A string explanation of the score. E.g. "Homework 1 - Ohms Law - 83% (5/6)"
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category: A string identifying the category. Items with the same category are grouped together
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in the display (for example, by color).
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prominent: A boolean value indicating that this section should be displayed as more prominent
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than other items.
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A dictionary in the grade_breakdown list has the following keys:
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percent: A float percentage in the breakdown. All percents should add up to the final percentage.
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detail: A string explanation of this breakdown. E.g. "Homework - 10% of a possible 15%"
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category: A string identifying the category. Items with the same category are grouped together
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in the display (for example, by color).
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"""
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__metaclass__ = abc.ABCMeta
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@abc.abstractmethod
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def grade(self, grade_sheet, generate_random_scores=False):
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'''Given a grade sheet, return a dict containing grading information'''
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raise NotImplementedError
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class WeightedSubsectionsGrader(CourseGrader):
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"""
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This grader takes a list of tuples containing (grader, category_name, weight) and computes
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a final grade by totalling the contribution of each sub grader and multiplying it by the
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given weight. For example, the sections may be
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[ (homeworkGrader, "Homework", 0.15), (labGrader, "Labs", 0.15), (midtermGrader, "Midterm", 0.30),
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(finalGrader, "Final", 0.40) ]
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All items in section_breakdown for each subgrader will be combined. A grade_breakdown will be
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composed using the score from each grader.
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Note that the sum of the weights is not take into consideration. If the weights add up to
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a value > 1, the student may end up with a percent > 100%. This allows for sections that
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are extra credit.
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"""
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def __init__(self, sections):
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self.sections = sections
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def grade(self, grade_sheet, generate_random_scores=False):
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total_percent = 0.0
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section_breakdown = []
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grade_breakdown = []
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for subgrader, category, weight in self.sections:
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subgrade_result = subgrader.grade(grade_sheet, generate_random_scores)
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weighted_percent = subgrade_result['percent'] * weight
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section_detail = u"{0} = {1:.2%} of a possible {2:.2%}".format(category, weighted_percent, weight)
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total_percent += weighted_percent
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section_breakdown += subgrade_result['section_breakdown']
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grade_breakdown.append({'percent': weighted_percent, 'detail': section_detail, 'category': category})
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return {'percent': total_percent,
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'section_breakdown': section_breakdown,
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'grade_breakdown': grade_breakdown}
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class SingleSectionGrader(CourseGrader):
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"""
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This grades a single section with the format 'type' and the name 'name'.
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If the name is not appropriate for the short short_label or category, they each may
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be specified individually.
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"""
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def __init__(self, type, name, short_label=None, category=None):
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self.type = type
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self.name = name
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self.short_label = short_label or name
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self.category = category or name
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def grade(self, grade_sheet, generate_random_scores=False):
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found_score = None
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if self.type in grade_sheet:
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for score in grade_sheet[self.type]:
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if score.section == self.name:
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found_score = score
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break
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if found_score or generate_random_scores:
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if generate_random_scores: # for debugging!
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earned = random.randint(2, 15)
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possible = random.randint(earned, 15)
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else: # We found the score
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earned = found_score.earned
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possible = found_score.possible
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percent = earned / float(possible)
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detail = u"{name} - {percent:.0%} ({earned:.3n}/{possible:.3n})".format(
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name=self.name,
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percent=percent,
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earned=float(earned),
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possible=float(possible)
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)
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else:
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percent = 0.0
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detail = u"{name} - 0% (?/?)".format(name=self.name)
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breakdown = [{'percent': percent, 'label': self.short_label,
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'detail': detail, 'category': self.category, 'prominent': True}]
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return {'percent': percent,
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'section_breakdown': breakdown,
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#No grade_breakdown here
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}
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class AssignmentFormatGrader(CourseGrader):
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"""
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Grades all sections matching the format 'type' with an equal weight. A specified
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number of lowest scores can be dropped from the calculation. The minimum number of
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sections in this format must be specified (even if those sections haven't been
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written yet).
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min_count defines how many assignments are expected throughout the course. Placeholder
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scores (of 0) will be inserted if the number of matching sections in the course is < min_count.
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If there number of matching sections in the course is > min_count, min_count will be ignored.
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show_only_average is to suppress the display of each assignment in this grader and instead
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only show the total score of this grader in the breakdown.
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hide_average is to suppress the display of the total score in this grader and instead
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only show each assignment in this grader in the breakdown.
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If there is only a single assignment in this grader, then it acts like a SingleSectionGrader
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and returns only one entry for the grader. Since the assignment and the total are the same,
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the total is returned but is not labeled as an average.
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category should be presentable to the user, but may not appear. When the grade breakdown is
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displayed, scores from the same category will be similar (for example, by color).
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section_type is a string that is the type of a singular section. For example, for Labs it
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would be "Lab". This defaults to be the same as category.
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short_label is similar to section_type, but shorter. For example, for Homework it would be
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"HW".
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starting_index is the first number that will appear. For example, starting_index=3 and
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min_count = 2 would produce the labels "Assignment 3", "Assignment 4"
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"""
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def __init__(self, type, min_count, drop_count, category=None, section_type=None, short_label=None,
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show_only_average=False, hide_average=False, starting_index=1):
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self.type = type
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self.min_count = min_count
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self.drop_count = drop_count
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self.category = category or self.type
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self.section_type = section_type or self.type
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self.short_label = short_label or self.type
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self.show_only_average = show_only_average
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self.starting_index = starting_index
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self.hide_average = hide_average
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def grade(self, grade_sheet, generate_random_scores=False):
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def total_with_drops(breakdown, drop_count):
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'''calculates total score for a section while dropping lowest scores'''
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#create an array of tuples with (index, mark), sorted by mark['percent'] descending
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sorted_breakdown = sorted(enumerate(breakdown), key=lambda x: -x[1]['percent'])
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# A list of the indices of the dropped scores
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dropped_indices = []
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if drop_count > 0:
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dropped_indices = [x[0] for x in sorted_breakdown[-drop_count:]]
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aggregate_score = 0
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for index, mark in enumerate(breakdown):
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if index not in dropped_indices:
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aggregate_score += mark['percent']
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if (len(breakdown) - drop_count > 0):
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aggregate_score /= len(breakdown) - drop_count
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return aggregate_score, dropped_indices
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#Figure the homework scores
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scores = grade_sheet.get(self.type, [])
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breakdown = []
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for i in range(max(self.min_count, len(scores))):
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if i < len(scores) or generate_random_scores:
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if generate_random_scores: # for debugging!
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earned = random.randint(2, 15)
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possible = random.randint(earned, 15)
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section_name = "Generated"
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else:
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earned = scores[i].earned
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possible = scores[i].possible
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section_name = scores[i].section
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percentage = earned / float(possible)
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summary_format = u"{section_type} {index} - {name} - {percent:.0%} ({earned:.3n}/{possible:.3n})"
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summary = summary_format.format(
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index=i + self.starting_index,
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section_type=self.section_type,
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name=section_name,
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percent=percentage,
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earned=float(earned),
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possible=float(possible)
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)
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else:
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percentage = 0
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summary = u"{section_type} {index} Unreleased - 0% (?/?)".format(
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index=i + self.starting_index,
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section_type=self.section_type
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)
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short_label = u"{short_label} {index:02d}".format(
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index=i + self.starting_index,
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short_label=self.short_label
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)
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breakdown.append({'percent': percentage, 'label': short_label,
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'detail': summary, 'category': self.category})
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total_percent, dropped_indices = total_with_drops(breakdown, self.drop_count)
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for dropped_index in dropped_indices:
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breakdown[dropped_index]['mark'] = {'detail': u"The lowest {drop_count} {section_type} scores are dropped."
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.format(drop_count=self.drop_count, section_type=self.section_type)}
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if len(breakdown) == 1:
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# if there is only one entry in a section, suppress the existing individual entry and the average,
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# and just display a single entry for the section. That way it acts automatically like a
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# SingleSectionGrader.
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total_detail = u"{section_type} = {percent:.0%}".format(
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percent=total_percent,
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section_type=self.section_type,
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)
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total_label = u"{short_label}".format(short_label=self.short_label)
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breakdown = [{'percent': total_percent, 'label': total_label,
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'detail': total_detail, 'category': self.category, 'prominent': True}, ]
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else:
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total_detail = u"{section_type} Average = {percent:.0%}".format(
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percent=total_percent,
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section_type=self.section_type
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)
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total_label = u"{short_label} Avg".format(short_label=self.short_label)
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if self.show_only_average:
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breakdown = []
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if not self.hide_average:
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breakdown.append({'percent': total_percent, 'label': total_label,
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'detail': total_detail, 'category': self.category, 'prominent': True})
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return {'percent': total_percent,
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'section_breakdown': breakdown,
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#No grade_breakdown here
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}
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