Gapotchenko.FX.Linq
2024.1.3
Prefix Reserved
dotnet add package Gapotchenko.FX.Linq --version 2024.1.3
NuGet\Install-Package Gapotchenko.FX.Linq -Version 2024.1.3
<PackageReference Include="Gapotchenko.FX.Linq" Version="2024.1.3" />
paket add Gapotchenko.FX.Linq --version 2024.1.3
#r "nuget: Gapotchenko.FX.Linq, 2024.1.3"
// Install Gapotchenko.FX.Linq as a Cake Addin #addin nuget:?package=Gapotchenko.FX.Linq&version=2024.1.3 // Install Gapotchenko.FX.Linq as a Cake Tool #tool nuget:?package=Gapotchenko.FX.Linq&version=2024.1.3
Overview
The module provides primitives for functional processing of data sequences.
Memoize
Memoization is a pillar of functional data processing. You already met it quite often albeit in somewhat masked forms.
Gapotchenko.FX.Linq
module provides the Memoize()
extension method for IEnumerable<T>
types.
You can use it like this:
using Gapotchenko.FX.Linq;
var files = Directory.EnumerateFiles(".", "*.txt").Select(Path.GetFileName).Memoize();
Console.WriteLine("A text file with an upper case letter is present: {0}", files.Any(x => x.Any(char.IsUpper)));
Console.WriteLine("A text file with a name longer than 12 letters is present: {0}", files.Any(x => x.Length > 12));
Memoize()
caches the already retrieved elements of a sequence, and does it lazily.
.NET developers often use ToList()
and ToArray()
methods for the very same purpose.
But those methods are eager, as they retrieve all elements of a sequence in one shot.
This often leads to suboptimal performance of an otherwise sound functional algorithm.
Memoize()
solves that. This is the method you are going to use the most for LINQ caching.
ScalarOrDefault
The second most popular primitive provided by Gapotchenko.FX.Linq
module is ScalarOrDefault()
method.
It is similar to SingleOrDefault()
provided by conventional .NET but has one big difference: ScalarOrDefault()
does not throw an exception when sequence contains multiple elements.
SingleOrDefault() Semantics
using System.Linq;
new string[0].SingleOrDefault(); // returns null
new[] { "A" }.SingleOrDefault(); // returns "A"
new[] { "A", "B" }.SingleOrDefault(); // throws an exception 😞
ScalarOrDefault() Semantics
using Gapotchenko.FX.Linq;
new string[0].ScalarOrDefault(); // returns null
new[] { "A" }.ScalarOrDefault(); // returns "A"
new[] { "A", "B" }.ScalarOrDefault(); // returns null 👍
In practice, ScalarOrDefault()
semantics is a big win as it allows you to safely determine whether a given query converges to a scalar result.
DistinctBy
Returns distinct elements from a sequence by using the default equality comparer on the keys extracted by a specified selector function.
The method is similar to Distinct()
method provided by the stock System.Linq
namespace, but allows to specify a selector function in order to differentiate the elements by a specific criteria.
Let's take a look at example:
using Gapotchenko.FX.Linq;
var source = new[]
{
new { FirstName = "Alex", LastName = "Cooper" },
new { FirstName = "John", LastName = "Walker" },
new { FirstName = "Alex", LastName = "The Great" },
new { FirstName = "Jeremy", LastName = "Doer" }
};
var query = source.DistinctBy(x => x.FirstName);
foreach (var i in query)
Console.WriteLine(i);
The code produces the following output:
{ FirstName = Alex, LastName = Cooper }
{ FirstName = John, LastName = Walker }
{ FirstName = Jeremy, LastName = Doer }
MinBy/MaxBy
Returns a minimum/maximum value in a sequence according to a specified key selector function.
Let's take a look at example:
using Gapotchenko.FX.Linq;
var source = new[]
{
new { FirstName = "Alex", LastName = "Cooper", Age = 45 },
new { FirstName = "John", LastName = "Walker", Age = 17 },
new { FirstName = "Alex", LastName = "The Great", Age = 1500 },
new { FirstName = "Jeremy", LastName = "Doer", Age = 29 }
};
Console.WriteLine("The oldest person: {0}", source.MaxBy(x => x.Age));
Console.WriteLine("The youngest person: {0}", source.MinBy(x => x.Age));
The code produces the following output:
The oldest person: { FirstName = Alex, LastName = The Great, Age = 1500 }
The youngest person: { FirstName = John, LastName = Walker, Age = 17 }
MinOrDefault/MaxOrDefault
These methods augment the semantics of conventional Min
and Max
methods, allowing to return the default value when the input sequence is empty.
Conventional Min
and Max
methods just throw an exception in that case.
Other Modules
Let's continue with a look at some other modules provided by Gapotchenko.FX:
- Gapotchenko.FX
- Gapotchenko.FX.AppModel.Information
- Gapotchenko.FX.Collections
- Gapotchenko.FX.Console
- Gapotchenko.FX.Data
- Gapotchenko.FX.Diagnostics
- Gapotchenko.FX.IO
- ➴ Gapotchenko.FX.Linq
- Gapotchenko.FX.Math
- Gapotchenko.FX.Memory
- Gapotchenko.FX.Security.Cryptography
- Gapotchenko.FX.Text
- Gapotchenko.FX.Threading
- Gapotchenko.FX.Tuples
Or look at the full list of modules.
Product | Versions Compatible and additional computed target framework versions. |
---|---|
.NET | net5.0 is compatible. net5.0-windows was computed. net6.0 is compatible. net6.0-android was computed. net6.0-ios was computed. net6.0-maccatalyst was computed. net6.0-macos was computed. net6.0-tvos was computed. net6.0-windows was computed. net7.0 is compatible. net7.0-android was computed. net7.0-ios was computed. net7.0-maccatalyst was computed. net7.0-macos was computed. net7.0-tvos was computed. net7.0-windows was computed. net8.0 is compatible. net8.0-android was computed. net8.0-browser was computed. net8.0-ios was computed. net8.0-maccatalyst was computed. net8.0-macos was computed. net8.0-tvos was computed. net8.0-windows was computed. net9.0 is compatible. |
.NET Core | netcoreapp2.0 was computed. netcoreapp2.1 is compatible. netcoreapp2.2 was computed. netcoreapp3.0 is compatible. netcoreapp3.1 was computed. |
.NET Standard | netstandard2.0 is compatible. netstandard2.1 is compatible. |
.NET Framework | net461 is compatible. net462 was computed. net463 was computed. net47 was computed. net471 is compatible. net472 is compatible. net48 was computed. net481 was computed. |
MonoAndroid | monoandroid was computed. |
MonoMac | monomac was computed. |
MonoTouch | monotouch was computed. |
Tizen | tizen40 was computed. tizen60 was computed. |
Xamarin.iOS | xamarinios was computed. |
Xamarin.Mac | xamarinmac was computed. |
Xamarin.TVOS | xamarintvos was computed. |
Xamarin.WatchOS | xamarinwatchos was computed. |
-
.NETCoreApp 2.1
- Gapotchenko.FX (>= 2024.1.3)
-
.NETCoreApp 3.0
- Gapotchenko.FX (>= 2024.1.3)
-
.NETFramework 4.6.1
- Gapotchenko.FX (>= 2024.1.3)
- System.ValueTuple (>= 4.5.0)
-
.NETFramework 4.7.1
- Gapotchenko.FX (>= 2024.1.3)
-
.NETFramework 4.7.2
- Gapotchenko.FX (>= 2024.1.3)
-
.NETStandard 2.0
- Gapotchenko.FX (>= 2024.1.3)
-
.NETStandard 2.1
- Gapotchenko.FX (>= 2024.1.3)
-
net5.0
- Gapotchenko.FX (>= 2024.1.3)
-
net6.0
- Gapotchenko.FX (>= 2024.1.3)
-
net7.0
- Gapotchenko.FX (>= 2024.1.3)
-
net8.0
- Gapotchenko.FX (>= 2024.1.3)
-
net9.0
- Gapotchenko.FX (>= 2024.1.3)
NuGet packages (8)
Showing the top 5 NuGet packages that depend on Gapotchenko.FX.Linq:
Package | Downloads |
---|---|
Gapotchenko.FX.Collections
Provides additional data collections, primitives and polyfills for .NET: ConcurrentHashSet<T>, AssociativeArray<T>, PriorityQueue<T>, Deque<T>. |
|
Gapotchenko.FX.Linq.Expressions
The module provides primitives for LINQ expressions. |
|
Gapotchenko.FX.Profiles.Core
Represents the Core profile of Gapotchenko.FX. |
|
Gapotchenko.FX.Math.Geometry
The module provides primitives and operations for geometry math. |
|
Gapotchenko.FX.Math.Combinatorics
Provides math operations for combinatorics. |
GitHub repositories
This package is not used by any popular GitHub repositories.
Version | Downloads | Last updated |
---|---|---|
2024.1.3 | 799 | 11/10/2024 |
2022.2.7 | 2,260 | 5/1/2022 |
2022.2.5 | 1,962 | 5/1/2022 |
2022.1.4 | 2,039 | 4/6/2022 |
2021.2.21 | 2,095 | 1/21/2022 |
2021.2.20 | 2,028 | 1/17/2022 |
2021.1.5 | 1,108 | 7/6/2021 |
2020.2.2-beta | 610 | 11/21/2020 |
2020.1.15 | 916 | 11/5/2020 |
2020.1.9-beta | 570 | 7/14/2020 |
2020.1.8-beta | 541 | 7/14/2020 |
2020.1.7-beta | 591 | 7/14/2020 |
2020.1.1-beta | 657 | 2/11/2020 |
2019.3.7 | 949 | 11/4/2019 |
2019.2.20 | 940 | 8/13/2019 |
2019.1.151 | 1,023 | 3/30/2019 |