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from django.db import models
from django.contrib.auth.models import User
class GradingSystem(models.Model):
name = models.CharField(max_length=255, unique=True)
description = models.TextField(default='About the grading system!')
creator = models.ForeignKey(User, null=True, blank=True)
def get_grade(self, marks):
ranges = self.graderange_set.all()
lower_limits = ranges.values_list('lower_limit', flat=True)
upper_limits = ranges.values_list('upper_limit', flat=True)
lower_limit = self._get_lower_limit(marks, lower_limits)
upper_limit = self._get_upper_limit(marks, upper_limits)
grade_range = ranges.filter(lower_limit=lower_limit,
upper_limit=upper_limit).first()
if grade_range:
return grade_range.grade
def _get_upper_limit(self, marks, upper_limits):
greater_than = [upper_limit for upper_limit in upper_limits
if upper_limit > marks]
if greater_than:
return min(greater_than, key=lambda x: x-marks)
def _get_lower_limit(self, marks, lower_limits):
less_than = []
for lower_limit in lower_limits:
if lower_limit == marks:
return lower_limit
if lower_limit < marks:
less_than.append(lower_limit)
if less_than:
return max(less_than, key=lambda x: x-marks)
def __str__(self):
return self.name.title()
class GradeRange(models.Model):
system = models.ForeignKey(GradingSystem)
lower_limit = models.FloatField()
upper_limit = models.FloatField()
grade = models.CharField(max_length=10)
description = models.CharField(max_length=127, null=True, blank=True)
def __str__(self):
return self.system.name.title()
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