Sort the list based on multiple numeric condition using LINQ

Question

I want to sort a list based on 3 numeric conditions. I need to do this sorting based on the property called 'CompletionPercentage'. So the list should be sorted on below conditions

Filter the list where the percentage should be greater than 0 and less than 100
Next filter the list where the percentage is equal to 0
Next filter the list where the percentage is equal to 100

I have tried the below code but it is not working. Please help.

var data = myCollection
  .ToList()
  .Where(x => getCourses.CourseLevel.Contains(x.CourseLevel)
  .OrderBy(x => x.CompletionPercentage > 1 && x.CompletionPercentage < 99)
  .ThenBy(x => x.CompletionPercentage == 0)
  .ThenBy(x => x.CompletionPercentage == 100);

OrderBy and ThenBy are sorting operations, not filtering. If by filtering you mean "sorting", you might want to implement a custom IComparer. Can you clarify exactly what you want, perhaps with a worked example? — ProgrammingLlama
– ProgrammingLlama, Commented Aug 22, 2022 at 6:38
" but it is not working." can you be more precise? please post an input example, the expected output, but the most important part: the actual outcome. — Mong Zhu
– Mong Zhu, Commented Aug 22, 2022 at 6:42
what do you want to achieve, its not obvious because your words and code conflict? — Jodrell
– Jodrell, Commented Aug 22, 2022 at 6:56

Dmitrii Bychenko · Accepted Answer · 2022-08-22 07:09:00Z

2

I suggest mapping items into three groups as it's mentioned in the question:

.OrderBy(item => item.CompletionPercentage ==   0 ? 2
               : item.CompletionPercentage == 100 ? 3
               : 1)

Here we have running item (CompletionPercentage > 0 and CompletionPercentage < 100) be the 1st, then not started items (CompletionPercentage == 0) followed by completed items (CompletionPercentage == 100)

Code:

var data = myCollection
  .Where(item => getCourses.CourseLevel.Contains(item.CourseLevel)
  .OrderBy(item => item.CompletionPercentage ==   0 ? 2
                 : item.CompletionPercentage == 100 ? 3
                 : 1)
  .ThenBy(item => item.CompletionPercentage) // if you want order per cents as well 
  .ToList();            // if you want data to be List<T>

edited Aug 22, 2022 at 7:09

answered Aug 22, 2022 at 7:01

Dmitrii Bychenko

188k20 gold badges178 silver badges231 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

CodeLearner Over a year ago

Your code works fine. Thanks for your help! I tried the below piece of code which works too. But I will use code which is more readable.

var data = myCollection.ToList().Where(x => getCourses.CourseLevel.Contains(x.CourseLevel) &&tempList.Contains(x.CompletionPercentage)).OrderBy(x => x.CompletionPercentage > 1 && x.CompletionPercentage < 100).OrderBy(x => x.CompletionPercentage == 0).OrderBy(x => x.CompletionPercentage == 100);

Dmitrii Bychenko Over a year ago

@CodeLearner: in your current code: 1. .ToList() is premature materialization which can be dropped. 2. Do not use several .OrderBy, but OrderBy followed by ThenBy, ThenBy. 3. Be careful with ranges: x.CompletionPercentage > 1 - what if x.CompletionPercentage == 1? 4. Check if tempList.Contains(x.CompletionPercentage) condition is actually required.

Collectives™ on Stack Overflow

Sort the list based on multiple numeric condition using LINQ

1 Answer 1

2 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

2 Comments

Your Answer

Sign up or log in

Post as a guest

Related