LINQ Order By Descending with Null Values on Bottom

LINQ Order By Descending with Null Values on Bottom

To order a collection in descending order using LINQ, with null values sorted to the bottom, you can use the OrderByDescending method along with the null coalescing operator (??) to provide a default value for nulls. Here's an example:

var sortedList = list.OrderByDescending(x => x?.MyProperty ?? default).ToList();

In this example, list is a collection of objects that have a property named MyProperty. The OrderByDescending method is called on the collection, and the lambda expression x => x?.MyProperty ?? default is passed as the sorting criterion.

The ?. operator is used to safely access the MyProperty property of each object, since some objects in the collection may be null. The ?? operator is then used to provide a default value for nulls, which in this case is default, which will be null for reference types and 0 for value types.

The resulting sortedList will contain the objects from the original list sorted in descending order by the MyProperty property, with null values sorted to the bottom of the list.

Note that if you want to sort null values to the top of the list instead of the bottom, you can simply swap the order of the sorting criterion and the default value:

var sortedList = list.OrderByDescending(x => x?.MyProperty == null ? 0 : 1)
                     .ThenByDescending(x => x?.MyProperty).ToList();

In this example, the OrderByDescending method is called with a sorting criterion that returns 0 for null values and 1 for non-null values. The ThenByDescending method is then called to sort non-null values in descending order. This will result in null values being sorted to the top of the list, followed by non-null values sorted in descending order by the MyProperty property.

Examples

  1. "LINQ Order By Descending with Null Values on Bottom - basic usage"

    Description: Sort a collection in descending order with null values placed at the bottom.

    // Code:
var orderedDescendingNullsBottom = myCollection.OrderByDescending(item => item.Property, Comparer<object>.Default.NullsLast()).ToList();

  2. "LINQ Order By Descending with Null Values on Bottom - multiple properties"

    Description: Sort a collection in descending order with null values at the bottom based on multiple properties.

    // Code:
var orderedDescendingNullsBottomMultipleProperties = myCollection.OrderByDescending(item => item.Property1, Comparer<object>.Default.NullsLast()).ThenByDescending(item => item.Property2).ToList();

  3. "LINQ Order By Descending with Null Values on Bottom - custom comparer"

    Description: Implement a custom comparer to handle descending ordering with null values at the bottom.

    // Code:
var orderedDescendingNullsBottomCustomComparer = myCollection.OrderByDescending(item => item.Property, new CustomComparer()).ToList();

  4. "LINQ Order By Descending with Null Values on Bottom - case-insensitive sorting"

    Description: Perform case-insensitive descending sorting with null values at the bottom.

    // Code:
var orderedDescendingNullsBottomCaseInsensitive = myCollection.OrderByDescending(item => item.Property, StringComparer.OrdinalIgnoreCase.NullsLast()).ToList();

  5. "LINQ Order By Descending with Null Values on Bottom - specific value first"

    Description: Order a collection in descending order, placing items with a specific value first and handling nulls at the bottom.

    // Code:
var orderedDescendingNullsBottomSpecificFirst = myCollection.OrderByDescending(item => item.Property != specificValue ? 0 : 1).ThenByDescending(item => item.Property).ToList();

  6. "LINQ Order By Descending with Null Values on Bottom - use List sorting"

    Description: Convert the collection to a list and use the Sort method to handle null values at the bottom in descending order.

    // Code:
var orderedList = myCollection.ToList();
orderedList.Sort((a, b) => Comparer<object>.Default.Compare(b.Property, a.Property));

  7. "LINQ Order By Descending with Null Values on Bottom - dynamic ordering with custom condition"

    Description: Implement dynamic ordering with a custom condition, placing null values at the bottom in descending order.

    // Code:
var orderedDescendingNullsBottomDynamic = myCollection.OrderByDescending(item => item.Property == specificValue ? 0 : 1).ThenByDescending(item => item.Property).ToList();

  8. "LINQ Order By Descending with Null Values on Bottom - using CompareTo"

    Description: Utilize the CompareTo method to handle descending sorting with null values at the bottom.

    // Code:
var orderedDescendingNullsBottomCompareTo = myCollection.OrderByDescending(item => item.Property.CompareTo(specificValue)).ToList();

  9. "LINQ Order By Descending with Null Values on Bottom - using Concat for custom ordering"

    Description: Use Concat to place items with specific values first, followed by null values at the bottom in descending order.

    // Code:
var orderedDescendingNullsBottomConcat = myCollection.Where(item => item.Property == specificValue).Concat(myCollection.Where(item => item.Property == null)).ToList();

  10. "LINQ Order By Descending with Null Values on Bottom - using GroupBy"

    Description: Utilize GroupBy to place items with null values at the bottom in descending order.

    // Code:
var groupedAndOrdered = myCollection.GroupBy(item => item.Property == null).SelectMany(group => group.OrderByDescending(item => item.Property)).ToList();

More Tags

autofac resx dynamic-variables sentiment-analysis uialertcontroller beamer permission-denied standards confluent-platform imaplib

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