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Select with FuncTSource int TResult selector - Use to get ranking of elements

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On of the overloads of the Select extension methods also passes the index of the current item in the collection being selected. These are a few uses of it.

Get the “row number” of the items 

var rowNumbers = collection.OrderBy(item => item.Property1)
                           .ThenBy(item => item.Property2)
                           .ThenByDescending(item => item.Property3)
                           .Select((item, index) => new { Item = item, RowNumber = index })
                           .ToList();

Get the rank of an item within its group 

var rankInGroup = collection.GroupBy(item => item.Property1)
                            .OrderBy(group => group.Key)
                            .SelectMany(group => group.OrderBy(item => item.Property2)
                                                   .ThenByDescending(item => item.Property3)
                                                   .Select((item, index) => new 
                                                   { 
                                                       Item = item, 
                                                       RankInGroup = index 
                                                   })).ToList();

Get the ranking of groups (also known in Oracle as dense_rank) 

var rankOfBelongingGroup = collection.GroupBy(item => item.Property1)
                            .OrderBy(group => group.Key)
                            .Select((group, index) => new
                            {
                                Items = group,
                                Rank = index
                            })
                            .SelectMany(v => v.Items, (s, i) => new
                            {
                                Item = i,
                                DenseRank = s.Rank
                            }).ToList();

For testing this you can use: 

public class SomeObject
{
    public int Property1 { get; set; }
    public int Property2 { get; set; }
    public int Property3 { get; set; }

    public override string ToString()
    {
        return string.Join(", ", Property1, Property2, Property3);
    }
}

And data: 

List<SomeObject> collection = new List<SomeObject>
{
    new SomeObject { Property1 = 1, Property2 = 1, Property3 = 1},
    new SomeObject { Property1 = 1, Property2 = 2, Property3 = 1},
    new SomeObject { Property1 = 1, Property2 = 2, Property3 = 2},
    new SomeObject { Property1 = 2, Property2 = 1, Property3 = 1},
    new SomeObject { Property1 = 2, Property2 = 2, Property3 = 1},
    new SomeObject { Property1 = 2, Property2 = 2, Property3 = 1},
    new SomeObject { Property1 = 2, Property2 = 3, Property3 = 1}
};
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LINQ Queries:
* LINQ Queries
* Chaining methods
* First FirstOrDefault Last LastOrDefault Single and SingleOrDefault
* Except
* SelectMany
* Any
* JOINS
* 0Skip and Take
* Zip
* 09Defining a variable inside a Linq query let keyword
* Range and Repeat
* All
* Basics
* Aggregate
* Distinct
* SelectMany Flattening a sequence of sequences
* Query collection by type cast elements to type
* GroupBy
* Enumerating the Enumerable
* Where
* Contains
* Using SelectMany instead of nested loops
* Using Range with various Linq methods
* Sum
* SkipWhile
* ToDictionary
* SequenceEqual
* Query Ordering - OrderBy ThenBy OrderByDescending ThenByDescending
* Any and FirstOrDefault - best practice
* GroupBy one or multiple fields
* OrderBy
* ElementAt and ElementAtOrDefault
* ToLookup
* Joining multiple sequences
* Joining on multiple keys
* DefaultIfEmpty
* GroupBy Sum and Count
* Count and LongCount
* Linq Quantifiers
* Build your own Linq operators for IEnumerableT
* GroupJoin with outer range variable
* Incrementally building a query
* Concat
* Reverse
* Union
* Select - Transforming elements
* OrderByDescending
* TakeWhile
* Select with FuncTSource int TResult selector - Use to get ranking of elements
Table Of Contents
0 Getting Started With C#
1 Literals
2 Operators
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4 Equality Operator
5 Equals and GetHashCode
6 Null-Coalescing Operator
7 Null-Conditional Operators
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110 Async/Await, BackgroundWorker, Task and Thread examples
111 Async Await
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113 BackgroundWorker
114 Task Parallel Library
115 Making a variable thread safe
116 Lock Statement
117 Yield Keyword
118 Task Parallel Library TPL Dataflow Constructs
119 Functional Programming
120 Func delegates
121 Function with multiple return values
122 Binary Serialization
123 ICloneable
124 IComparable
125 Accessing Databases
126 Using SQLite
127 Caching
128 Code Contracts
129 Code Contracts and Assertions
130 Structural Design Patterns
131 Creational Design Patterns
132 Implementing Decorating Design Pattern
133 Implementing Flyweight Design Pattern
134 System.Management.Automation
135 Pointers
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137 Simulating C Unions with C# Structs
138 Reactive Extensions Rx
139 AsseblyInfo.cs examples
140 Creating Console Application
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142 ObservableCollection
143 Hash Functions
144 Generating Random Numbers
145 Cryptography
146 Unsafe Code in .NET
147 C# Script
148 Runtime Compile
149 Interoperability
150 .NET Compiler Platform Roslyn
151 Creating Own MessageBox in Windows Form Application
152 Including Font Resources
153 Garbage Collector
154 Windows Communication Foundation
155 Contributors