CODEWITHSUNDEEP
c#linq
Zong
Zong

Reputation: 133

Sort even numbers from List using LINQ

I am trying to display even numbers from a list of integers and sort them in ascending order. My code is:

public void EvenNumbers()
{
    List<int> ofNumbers = new List<int> { 1, 3, 2, 10, 15, 6, 8 };

    ofNumbers.Sort();
    var result = (from m in ofNumbers
                  where m % 2 == 0
                  select m).ToList();
}

But after reading Sorting a List I am trying to sort my list with the following code:

var values = new int[] { 5,7,3 };
values = values.OrderBy(p => p).ToList();

changing my code to this is not working

public void EvenNumbers()
{
    List<int> ofNumbers = new List<int> { 1, 3, 2, 10, 15, 6, 8 };
    
    var result = ofNumbers.OrderBy(from m in ofNumbers
                  where m % 2 == 0
                  select m).ToList();
}

What am I doing wrong here?

Upvotes: 1

Views: 1055

Answers (2)

SomeBody
SomeBody

Reputation: 8743

You are mixing query syntax with method syntax. The query syntax looks really close to normal SQL:

var result = (from m in ofNumbers
              where m % 2 == 0
              orderby m
              select m).ToList();

The method syntax expects lambda expressions:

var result = ofNumbers.Where(m => m % 2 == 0).OrderBy(m => m).ToList();

Both are compiled to the very same IL, hence you can just take the version you like most. I think the query syntax is preferred by beginners, whereas the method syntax is preferred by advanced C# coders (because it is more powerful).

Upvotes: 2

Grigory Zhadko
Grigory Zhadko

Reputation: 1848

The cause of the problem is that you are trying to combine two syntaxes:

  1. Extension methods syntax. (OrderBy() method)
  2. Query syntax (from, where, select, etc. keywords)

It would be better to use just one approach. Here are examples:

Extension methods:

var result = ofNumbers.Where(m => m % 2 == 0).OrderBy(m => m).ToList();

Query:

var result = (from m in ofNumbers
                where m % 2 == 0
                orderby m
                select m).ToList();

Upvotes: 2

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