月別: 2019年10月

class PetOwner
{
    public string Name { get; set; }
    public List<String> Pets { get; set; }
}

public static void SelectManyEx1()
{
    PetOwner[] petOwners = 
        { new PetOwner { Name="Higa, Sidney", 
              Pets = new List<string>{ "Scruffy", "Sam" } },
          new PetOwner { Name="Ashkenazi, Ronen", 
              Pets = new List<string>{ "Walker", "Sugar" } },
          new PetOwner { Name="Price, Vernette", 
              Pets = new List<string>{ "Scratches", "Diesel" } } };

    // Query using SelectMany().
    IEnumerable<string> query1 = petOwners.SelectMany(petOwner => petOwner.Pets);

    Console.WriteLine("Using SelectMany():");

    // Only one foreach loop is required to iterate 
    // through the results since it is a
    // one-dimensional collection.
    foreach (string pet in query1)
    {
        Console.WriteLine(pet);
    }

    // This code shows how to use Select() 
    // instead of SelectMany().
    IEnumerable<List<String>> query2 =
        petOwners.Select(petOwner => petOwner.Pets);

    Console.WriteLine("\nUsing Select():");

    // Notice that two foreach loops are required to 
    // iterate through the results
    // because the query returns a collection of arrays.
    foreach (List<String> petList in query2)
    {
        foreach (string pet in petList)
        {
            Console.WriteLine(pet);
        }
        Console.WriteLine();
    }
}

/*
 This code produces the following output:

 Using SelectMany():
 Scruffy
 Sam
 Walker
 Sugar
 Scratches
 Diesel

 Using Select():
 Scruffy
 Sam

 Walker
 Sugar

 Scratches
 Diesel
*/

class PetOwner

{

public string Name { get; set; }

public List<String> Pets { get; set; }

}

public static void SelectManyEx1()

{

PetOwner[] petOwners =

{ new PetOwner { Name="Higa, Sidney",

Pets = new List<string>{ "Scruffy", "Sam" } },

new PetOwner { Name="Ashkenazi, Ronen",

Pets = new List<string>{ "Walker", "Sugar" } },

new PetOwner { Name="Price, Vernette",

Pets = new List<string>{ "Scratches", "Diesel" } } };

// Query using SelectMany().

IEnumerable<string> query1 = petOwners.SelectMany(petOwner => petOwner.Pets);

Console.WriteLine("Using SelectMany():");

// Only one foreach loop is required to iterate

// through the results since it is a

// one-dimensional collection.

foreach (string pet in query1)

{

Console.WriteLine(pet);

}

// This code shows how to use Select()

// instead of SelectMany().

IEnumerable<List<String>> query2 =

petOwners.Select(petOwner => petOwner.Pets);

Console.WriteLine("\nUsing Select():");

// Notice that two foreach loops are required to

// iterate through the results

// because the query returns a collection of arrays.

foreach (List<String> petList in query2)

{

foreach (string pet in petList)

{

Console.WriteLine(pet);

}

Console.WriteLine();

}

This code produces the following output:

Using SelectMany():

Scruffy

Sam

Walker

Sugar

Scratches

Diesel

Using Select():

Scruffy

Sam

Walker

Sugar

Scratches

Diesel

参考 …

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カテゴリーリファレンスタグ SelectMany

Max

LINQマスター 2019年10月21日2019年10月22日 0

機能シーケンス内の要素の最大値を計算します。オーバーロード以下の型(6) ｘ Null許容有無(2) ｘ …

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カテゴリーリファレンスタグ Max

Min

LINQマスター 2019年10月21日2019年10月22日 0

機能シーケンス内の要素の最小値を計算します。オーバーロード以下の型(6) ｘ Null許容有無(2) ｘ …

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カテゴリーリファレンスタグ Min

Sum

LINQマスター 2019年10月21日2019年10月22日 0

機能シーケンス内の要素の合計を計算します。オーバーロード数値型の以下の型(5) ｘ Null許容有無(2 …

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カテゴリーリファレンスタグ Sum