CODEWITHSUNDEEP
pythondjango
Tom Fin
Tom Fin

Reputation: 123

Refactor this views code

I have the following code in one of my views. The problem is I can't figure out how to refactor it into just one for loop. The only difference is the 'item.' part. I need all three variable values in the same template so I don't think I can pass information from the urls.py. Any ideas of how I can rewrite this so I am not repeating myself?

Thanks.

def average(request):

    cal_list = []
    cal_list2 = []
    cal_list3 = []

    exams = Test.objects.filter(test__test_name__iexact="one")
    for item in exams:
        cal_list.append(int(item.start))
        result = sum(cal_list) / float(165) * 100
        result = result / len(cal_list)
        result = int(round(result))
        result = str(result) + '%'

    for item in exams:
        cal_list2.append(int(item.s1))
        result2 = sum(cal_list2) / float(165) * 100
        result2 = result2 / len(cal_list2)
        result2 = int(round(result2))
        result2 = str(result2) + '%'

    for item in exams:
        cal_list3.append(int(item.s2))
        result3 = sum(cal_list3) / float(165) * 100
        result3 = result3 / len(cal_list3)
        result3 = int(round(result3))
        result3 = str(result3) + '%'

    return direct_to_template(request, 'a.html', {'result': result, 'result2': result2, 'result3': result3})

Upvotes: 0

Views: 100

Answers (4)

dnozay
dnozay

Reputation: 24324

you can use the aggregate to perform the sum at the database layer.

from django.db import models

def average(request):
    queryset = Test.objects.filter(test__test_name__iexact="one")
    total = queryset.count()
    results = queryset.aggregate(
        result1=models.Sum('start'),
        result2=models.Sum('s1'),
        result3=models.Sum('s2'))
    def transform(resultsum):
        result = resultsum / float(165) * 100
        result = result / total
        result = int(round(result))
        result = str(result) + '%'
        return result
    result1 = transform(results['result1'])
    result2 = transform(results['result2'])
    result3 = transform(results['result3'])
    return direct_to_template(request, 'a.html', {'result': result1, 'result2': result2, 'result3': result3})

Upvotes: 0

Nathan Villaescusa
Nathan Villaescusa

Reputation: 17639

I would just create a function:

def calculate_result(items):
    items = tuple(int(i) for i in items)
    result = sum(items) / 16500.0
    result = result / len(items)
    return '%i' % round(result) + '%'

result0 = calculate_result(item.start for item in exams)
result1 = calculate_result(item.s1 for item in exams)
result2 = calculate_result(item.s2 for item in exams)

Upvotes: 1

Burhan Khalid
Burhan Khalid

Reputation: 174622

In your loop you keep overwriting the results value, so you can extrapolate that part:

for item in items:
   cal_list.append(int(item.start))
   cal_list2.append(int(item.s1))
   cal_list3.append(int(item.s2))

result = "%s%%" % round((sum(cal_list) / float(165) * 100) / len(cal_list))
result2 = "%s%%" % round((sum(cal_list2) / float(165) * 100) / len(cal_list2))
result3 = "%s%%" % round((sum(cal_list3) / float(165) * 100) / len(cal_list3))

Upvotes: 1

Senthil Kumaran
Senthil Kumaran

Reputation: 56881

There you go for the simplest refactoring, which saved the loop from iterating only on required things and moving the calculation out of the loop.

def average(request):

    cal_list = []
    cal_list2 = []
    cal_list3 = []

    exams = Test.objects.filter(test__test_name__iexact="one")
    for item in exams:
        cal_list.append(int(item.start))
        cal_list2.append(int(item.s1))
        cal_list3.append(int(item.s2))

    result = sum(cal_list) / float(165) * 100
    result = result / len(cal_list)
    result = int(round(result))
    result = str(result) + '%'

    result2 = sum(cal_list2) / float(165) * 100
    result2 = result2 / len(cal_list2)
    result2 = int(round(result2))
    result2 = str(result2) + '%'

    result3 = sum(cal_list3) / float(165) * 100
    result3 = result3 / len(cal_list3)
    result3 = int(round(result3))
    result3 = str(result3) + '%'

    return direct_to_template(request, 'a.html', {'result': result, 'result2': result2, 'result3': result3})

Upvotes: 0

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