Comparison to singleton
False should be expr is False629 results = transcript.course_result.all()
630 total_cr = 0
631 for sheet in results:
632 if last_course_being_final and sheet.finalized == False:633 last_course_being_final = False
634 sum += sheet.gpa*sheet.course.credit_hour
635 count += 1Comparison to singleton
None should be expr is None573 #grading_type = request.POST['Type']
574 scheme = 0
575 scsddc = request.POST['scsddc']
576 if scsddc == None or scsddc == "" or scsddc == "null":577 return JsonResponse({"Error": "Invalid scsddc"}, status=403)
578 csection = CourseSection.objects.get(scsddc=scsddc)
579 for student_info in csection.student_info.all():Comparison to singleton
None should be expr is None529def marks_info(request):
530 scsddc = request.POST['scsddc']
531 print(scsddc)
532 if scsddc == None or scsddc == "" or scsddc == "null":533 return JsonResponse({"Failed": "Invalid Input Parameters"}, status=403)
534 print(scsddc)
535 marks = SectionMarks.objects.filter(scsddc=scsddc).values()Comparison to singleton
None should be expr is None437 info = csection.student_info.get(student=student_info.student)
438
439 info.mark_sheet.Marks.add(new_a)
440 if info.mark_sheet.grand_total_marks == None:441 info.mark_sheet.grand_total_marks = 0.0
442 info.mark_sheet.grand_total_marks += float(section_marks.weightage)
443 info.mark_sheet.year = yearComparison to singleton
None should be expr is None240 scsddc = request.POST['scsddc']
241 marks_type = request.POST['marks_type']
242 marks_data = json.loads(request.POST['marks_data'])
243 if marks_type == None or marks_type == "" or scsddc == None or scsddc == "" or marks_data == None or marks_data == "":244 return JsonResponse({"Failed": "Invalid Input Parameters"}, status=403)
245 else:
246 try:Comparison to singleton
None should be expr is None240 scsddc = request.POST['scsddc']
241 marks_type = request.POST['marks_type']
242 marks_data = json.loads(request.POST['marks_data'])
243 if marks_type == None or marks_type == "" or scsddc == None or scsddc == "" or marks_data == None or marks_data == "":244 return JsonResponse({"Failed": "Invalid Input Parameters"}, status=403)
245 else:
246 try:Comparison to singleton
None should be expr is None240 scsddc = request.POST['scsddc']
241 marks_type = request.POST['marks_type']
242 marks_data = json.loads(request.POST['marks_data'])
243 if marks_type == None or marks_type == "" or scsddc == None or scsddc == "" or marks_data == None or marks_data == "":244 return JsonResponse({"Failed": "Invalid Input Parameters"}, status=403)
245 else:
246 try:Comparison to singleton
None should be expr is None149 def post(self, request):
150 marks_type = request.POST['marks_type']
151 scsddc = request.POST['scsddc']
152 if marks_type == None or marks_type == "" or scsddc == None or scsddc == "" or scsddc == "null":153 return JsonResponse({"Failure": "Parameters Are Not Valid"}, safe=False, status=403)
154 student_marks = StudentMarks.objects.filter(
155 marks_type=marks_type, scsddc=scsddc)Comparison to singleton
None should be expr is None149 def post(self, request):
150 marks_type = request.POST['marks_type']
151 scsddc = request.POST['scsddc']
152 if marks_type == None or marks_type == "" or scsddc == None or scsddc == "" or scsddc == "null":153 return JsonResponse({"Failure": "Parameters Are Not Valid"}, safe=False, status=403)
154 student_marks = StudentMarks.objects.filter(
155 marks_type=marks_type, scsddc=scsddc)Comparison to singleton
True should be expr is True166 if dep is None or deg is None:
167 return JsonResponse({'message': 'Invalid Student', 'condition': True}, status=401)
168
169 if(deg.registrations_open == True):170 return JsonResponse({'message': 'Regisrations are Active', 'condition': True}, status=200)
171 else:
172 return JsonResponse({'message': 'Regisrations are NOT Active', 'condition': False}, status=200)Comparison to singleton
False should be expr is False236 if user is None:
237 return JsonResponse({'message': "Invalid Id Or Password", 'status': 'failure'}, status=403)
238
239 if user.is_student == False:240 return JsonResponse({'message': 'User is Not a Student',
241 'condtion': False, 'status': 'failure'}, status=401)
242Comparison to singleton
True should be expr is True391 semester = Semester.objects.get(semester_code=request.POST['semester'])
392 challan, created = FeeChallan.objects.get_or_create(
393 student=student, semester=semester)
394 if created == True:395 transcript = Transcript.objects.get_or_create(
396 student=student, semester=Semester.objects.get(current_semester=True))[0]
397 challan.coActivity_charges = semester.co_circular_feeComparison to singleton
None should be expr is None484 def post(self, request):
485 section = request.POST['section']
486 code = request.POST['code']
487 if section == None or section == "" or section == "null" or code == None or code == "" or code == "null":488 return JsonResponse({"Failed": "Invalid Input Parameters"}, status=403)
489 else:
490 student = Student.objects.get(user=request.user)Comparison to singleton
None should be expr is None484 def post(self, request):
485 section = request.POST['section']
486 code = request.POST['code']
487 if section == None or section == "" or section == "null" or code == None or code == "" or code == "null":488 return JsonResponse({"Failed": "Invalid Input Parameters"}, status=403)
489 else:
490 student = Student.objects.get(user=request.user)
Description
Comparisons to the singleton objects, like True, False, and None, should be done with identity, not equality. Use is or is not.
Identity checks are faster than equality checks.
Also, the equality checks can result in unintended behaviour in some cases:
>>> 1 is True
False
>>> 1 == True
True
>>> 1.0 is True
False
>>> 1.0 == True
True
Bad practice
value = fx()
if value == True: # `==` can cause unintended behaviour
print(value)
if value != None:
print(value)
Recommended
value = fx()
if value is True: # `is` for Identity comparison
print(value)
if value is not None:
print(value)
Exceptions:
Equality comparisons might be required in some cases, especially in SQLAlchemy, SQLObject, ORMs, etc. In these cases, it is safe to ignore this issue.