147 lines
4.8 KiB
Python
147 lines
4.8 KiB
Python
"""
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Profile Distributions
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Aggregate sums for values of fields in students profiles.
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For example:
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The distribution in a course for gender might look like:
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'gender': {
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'type': 'EASY_CHOICE',
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'data': {
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'no_data': 1234,
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'm': 5678,
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'o': 2134,
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'f': 5678
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},
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'display_names': {
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'no_data': 'No Data',
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'm': 'Male',
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'o': 'Other',
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'f': 'Female'
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}
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"""
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from django.db.models import Count
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from student.models import CourseEnrollment, UserProfile
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_EASY_CHOICE_FEATURES = ('gender', 'level_of_education')
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_OPEN_CHOICE_FEATURES = ('year_of_birth',)
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AVAILABLE_PROFILE_FEATURES = _EASY_CHOICE_FEATURES + _OPEN_CHOICE_FEATURES
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DISPLAY_NAMES = {
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'gender': 'Gender',
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'level_of_education': 'Level of Education',
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'year_of_birth': 'Year Of Birth',
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}
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class ProfileDistribution(object):
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"""
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Container for profile distribution data
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`feature` is the name of the distribution feature
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`feature_display_name` is the display name of feature
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`data` is a dictionary of the distribution
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`type` is either 'EASY_CHOICE' or 'OPEN_CHOICE'
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`choices_display_names` is a dict if the distribution is an 'EASY_CHOICE'
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"""
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class ValidationError(ValueError):
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""" Error thrown if validation fails. """
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pass
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def __init__(self, feature):
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self.feature = feature
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self.feature_display_name = DISPLAY_NAMES[feature]
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def validate(self):
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"""
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Validate this profile distribution.
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Throws ProfileDistribution.ValidationError
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"""
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def validation_assert(predicate):
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if not predicate:
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raise ProfileDistribution.ValidationError()
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validation_assert(isinstance(self.feature, str))
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validation_assert(isinstance(self.feature_display_name, str))
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validation_assert(self.type in ['EASY_CHOICE', 'OPEN_CHOICE'])
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validation_assert(isinstance(self.data, dict))
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if self.type == 'EASY_CHOICE':
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validation_assert(isinstance(self.choices_display_names, dict))
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def profile_distribution(course_id, feature):
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"""
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Retrieve distribution of students over a given feature.
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feature is one of AVAILABLE_PROFILE_FEATURES.
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Returns a ProfileDistribution instance.
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NOTE: no_data will appear as a key instead of None to be compatible with the json spec.
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data types are
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EASY_CHOICE - choices with a restricted domain, e.g. level_of_education
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OPEN_CHOICE - choices with a larger domain e.g. year_of_birth
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"""
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if not feature in AVAILABLE_PROFILE_FEATURES:
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raise ValueError(
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"unsupported feature requested for distribution '{}'".format(
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feature)
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)
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prd = ProfileDistribution(feature)
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if feature in _EASY_CHOICE_FEATURES:
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prd.type = 'EASY_CHOICE'
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if feature == 'gender':
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raw_choices = UserProfile.GENDER_CHOICES
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elif feature == 'level_of_education':
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raw_choices = UserProfile.LEVEL_OF_EDUCATION_CHOICES
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# short name and display nae (full) of the choices.
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choices = [(short, full)
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for (short, full) in raw_choices] + [('no_data', 'No Data')]
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distribution = {}
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for (short, full) in choices:
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if feature == 'gender':
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count = CourseEnrollment.objects.filter(
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course_id=course_id, user__profile__gender=short
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).count()
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elif feature == 'level_of_education':
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count = CourseEnrollment.objects.filter(
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course_id=course_id, user__profile__level_of_education=short
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).count()
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distribution[short] = count
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prd.data = distribution
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prd.choices_display_names = dict(choices)
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elif feature in _OPEN_CHOICE_FEATURES:
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prd.type = 'OPEN_CHOICE'
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profiles = UserProfile.objects.filter(
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user__courseenrollment__course_id=course_id)
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query_distribution = profiles.values(
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feature).annotate(Count(feature)).order_by()
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# query_distribution is of the form [{'featureval': 'value1', 'featureval__count': 4},
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# {'featureval': 'value2', 'featureval__count': 2}, ...]
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distribution = dict((vald[feature], vald[feature + '__count'])
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for vald in query_distribution)
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# distribution is of the form {'value1': 4, 'value2': 2, ...}
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# change none to no_data for valid json key
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if None in distribution:
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distribution['no_data'] = distribution.pop(None)
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# django does not properly count NULL values, so the above will alwasy be 0.
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# this correctly counts null values
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distribution['no_data'] = profiles.filter(
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**{feature: None}
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).count()
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prd.data = distribution
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prd.validate()
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return prd
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