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Sorting Data

A sorting operation orders the elements of a sequence based on one or more attributes. The first sort criterion performs a primary sort on the elements. By specifying a second sort criterion, you can sort the elements within each primary sort group.

The following illustration shows the results of an alphabetical sort operation on a sequence of characters.

LINQ Sorting Operation

The standard query operator methods that sort data are listed in the following section.

Method Name

Description

C# Query Expression Syntax

Visual Basic Query Expression Syntax

More Information

OrderBy

Sorts values in ascending order.

orderby

Order By

Enumerable.OrderBy

Queryable.OrderBy

OrderByDescending

Sorts values in descending order.

orderby … descending

Order By … Descending

Enumerable.OrderByDescending

Queryable.OrderByDescending

ThenBy

Performs a secondary sort in ascending order.

orderby …, …

Order By …, …

Enumerable.ThenBy

Queryable.ThenBy

ThenByDescending

Performs a secondary sort in descending order.

orderby …, … descending

Order By …, … Descending

Enumerable.ThenByDescending

Queryable.ThenByDescending

Reverse

Reverses the order of the elements in a collection.

Not applicable.

Not applicable.

Enumerable.Reverse(Of TSource)

Queryable.Reverse(Of TSource)

Primary Sort Examples

Primary Ascending Sort

The following example demonstrates how to use the orderby (Order By in Visual Basic) clause in a LINQ query to sort the strings in an array by string length, in ascending order.

Dim words() As String = {"the", "quick", "brown", "fox", "jumps"}

Dim sortQuery = From word In words _
                Order By word.Length _
                Select word

Dim sb As New System.Text.StringBuilder()
For Each str As String In sortQuery
    sb.AppendLine(str)
Next 

' Display the results.
MsgBox(sb.ToString())

' This code produces the following output: 

' the 
' fox 
' quick 
' brown 
' jumps

Primary Descending Sort

The next example demonstrates how to use the orderby descending (Order By Descending in Visual Basic) clause in a LINQ query to sort the strings by their first letter, in descending order.

Dim words() As String = {"the", "quick", "brown", "fox", "jumps"}

Dim sortQuery = From word In words _
                Order By word.Substring(0, 1) Descending _
                Select word

Dim sb As New System.Text.StringBuilder()
For Each str As String In sortQuery
    sb.AppendLine(str)
Next 

' Display the results.
MsgBox(sb.ToString())

' This code produces the following output: 

' the 
' quick 
' jumps 
' fox 
' brown

Secondary Sort Examples

Secondary Ascending Sort

The following example demonstrates how to use the orderby (Order By in Visual Basic) clause in a LINQ query to perform a primary and secondary sort of the strings in an array. The strings are sorted primarily by length and secondarily by the first letter of the string, both in ascending order.

Dim words() As String = {"the", "quick", "brown", "fox", "jumps"}

Dim sortQuery = From word In words _
                Order By word.Length, word.Substring(0, 1) _
                Select word

Dim sb As New System.Text.StringBuilder()
For Each str As String In sortQuery
    sb.AppendLine(str)
Next 

' Display the results.
MsgBox(sb.ToString())

' This code produces the following output: 

' fox 
' the 
' brown 
' jumps 
' quick

Secondary Descending Sort

The next example demonstrates how to use the orderby descending (Order By Descending in Visual Basic) clause in a LINQ query to perform a primary sort, in ascending order, and a secondary sort, in descending order. The strings are sorted primarily by length and secondarily by the first letter of the string.

Dim words() As String = {"the", "quick", "brown", "fox", "jumps"}

Dim sortQuery = From word In words _
                Order By word.Length, word.Substring(0, 1) Descending _
                Select word

Dim sb As New System.Text.StringBuilder()
For Each str As String In sortQuery
    sb.AppendLine(str)
Next 

' Display the results.
MsgBox(sb.ToString())

' This code produces the following output: 

' fox 
' the 
' quick 
' jumps 
' brown

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