https://github.com/karenpayneoregon/indexes-ranges-csharp
C# 8 indexes and ranges code samples
https://github.com/karenpayneoregon/indexes-ranges-csharp
csharp indexes ranges unit-testing visual-studio
Last synced: about 2 months ago
JSON representation
C# 8 indexes and ranges code samples
- Host: GitHub
- URL: https://github.com/karenpayneoregon/indexes-ranges-csharp
- Owner: karenpayneoregon
- Created: 2021-05-10T03:23:11.000Z (about 5 years ago)
- Default Branch: master
- Last Pushed: 2021-06-06T19:39:30.000Z (about 5 years ago)
- Last Synced: 2025-03-23T18:17:23.519Z (about 1 year ago)
- Topics: csharp, indexes, ranges, unit-testing, visual-studio
- Language: C#
- Homepage:
- Size: 129 KB
- Stars: 0
- Watchers: 1
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: readme.md
Awesome Lists containing this project
README
# C# 8 Ranges and Indices in detail
 
---
Learn how to work with C# 8 Range and Indexes going beyond the code samples found done by Microsoft and other entities on the web.
There are code samples that work with
- Strings
- Dates
- Numerics
- Classes/list
Each code sample are done in unit test methods where the category/trait for each are marked with `[TestTraits(Trait.xxxx)]` where xxxx has been defined in the following `enum`.
```csharp
public enum Trait
{
PlaceHolder,
RangesIndices,
CreateTextFile,
Contacts,
Cities,
Strings,
Dates,
Numbers
}
```
# Documentation
- Each unit test describes it's intent and verified with assertions.
- Some test use [IEqualityComparer](https://docs.microsoft.com/en-us/dotnet/api/system.collections.generic.iequalitycomparer-1?view=net-5.0)<T> to compare actual results with expected results as shown below.
```csharp
using System;
using System.Collections.Generic;
namespace RangeUnitTest.Classes
{
public class ContactIdFirstNameLastNameEqualityComparer : IEqualityComparer
{
public bool Equals(Contacts x, Contacts y)
{
if (ReferenceEquals(x, y)) return true;
if (ReferenceEquals(x, null)) return false;
if (ReferenceEquals(y, null)) return false;
if (x.GetType() != y.GetType()) return false;
return x.ContactId == y.ContactId && x.FirstName == y.FirstName && x.LastName == y.LastName;
}
public int GetHashCode(Contacts obj)
{
return HashCode.Combine(obj.ContactId, obj.FirstName, obj.LastName);
}
}
}
```
# Data sources
For many of the code samples, information is read from text files
- Using json
``` csharp
using System;
using System.Collections.Generic;
using System.IO;
namespace RangeUnitTest.Classes
{
public class MockedData
{
public static string ContactFileName { get; } = "contacts.json";
public static List ReadContacts()
{
try
{
var json = File.ReadAllText(ContactFileName);
return JSonHelper.ConvertJSonToObject>(json);
}
catch (Exception)
{
return null;
}
}
}
}
```
- Reading plain text
```csharp
using System.IO;
using System.Linq;
namespace RangeUnitTest.Classes
{
public class FileOperations
{
public static string[] OregonCities() => File.ReadAllLines("OregonCityNames.txt");
public static string[] OregonCitiesFirstTen() => OregonCities().Take(10).ToArray();
}
}
```
# Base classes/Interfaces
To keep test methods clean, base classes, partial classes and Interfaces are used.
# Visualization
To get a visual representation of indices on a list see the files under the `Dump` folder in tangent with various test methods.
# Example test method
```csharp
[TestMethod]
[TestTraits(Trait.Contacts)]
public void BetweenContacts_1()
{
/*
* First contact for between
*/
var firstContact = new ContactName() { FirstName = "Fr�d�rique", LastName = "Citeaux" };
/*
* Last contact for between
*/
var lastContact = new ContactName() { FirstName = "Elizabeth", LastName = "Brown" };
var contactsArray = MockedData.ReadContacts().ToArray();
var contacts = contactsArray.ContactsListIndices();
var (startIndex, endIndex) = contacts.BetweenContacts(firstContact, lastContact);
var contactsBetweenTwo = contactsArray[startIndex..endIndex];
Assert.IsTrue(
contactsBetweenTwo
.SequenceEqual(
ExpectedContacts,
new ContactIdFirstNameLastNameEqualityComparer()));
}
```
---
**From Microsoft**
Ranges and indices provide a succinct syntax for accessing single elements or ranges in a sequence.
An index expression typically returns the type of the elements of a sequence. A range expression typically returns the same sequence type as the source sequence.
# Microsoft docs
[Explore indexs and ranges](https://docs.microsoft.com/en-us/dotnet/csharp/whats-new/tutorials/ranges-indexes)
# See also
[Visual Studio: Different methods to display unit test](https://social.technet.microsoft.com/wiki/contents/articles/51303.visual-studio-different-methods-to-display-unit-test.aspx)
[Get started with Live Unit Testing](https://docs.microsoft.com/en-us/visualstudio/test/live-unit-testing-start?tabs=csharp&view=vs-2019)
[Original GitHub page](https://github.com/karenpayneoregon/karenpayneoregon.github.io/blob/master/csharp/indices-ranges.md)