C# Operators Null-coalescing ,Null-conditional and Chaining

The Null-coalescing ,Null-conditional and Chaining C# Operators #csharp #programming #programmers #Coding #code #CodeNewbie #100DaysOfCode pic.twitter.com/G4rsiyVrFX

— San (@santoshpoojari3) April 19, 2020

C# Local Function use only just once

C# Local Function -USE JUST ONCE#csharp #developers #Developer #100DaysOfCode #Coding #code #CodeNewbie #codes #programming #programmers #programmer pic.twitter.com/3wxYYhDmdg

— San (@santoshpoojari3) April 20, 2020

c# Array SequenceEqual() and Reverse()

C# Array to compare ,SequenceEqual() and Reverse()

int[] arr1 = new int[] { 1,2,3};
int[] arr2 = new int[] { 3,2,1 };

Console.WriteLine(arr1.SequenceEqual(arr2)); // false
Console.WriteLine(arr1.Reverse().SequenceEqual(arr2)); // true#csharp #programming #programmers #code

— San (@santoshpoojari3) April 21, 2020

C# Collection by its capability, use it wisely

Best Practice C# Make use of AS operator for casting object

Remember to use As operator, here is the simple reason to avoid unnecessary exception is thrown.

With exception

Student s= new Student();
Object o = s;

var newStudent=  (string)o;// Exception casting not possible

As Operator to rescue, AS operator returns null if not compatible else right conversion object type

Student s= new Student();
Object o = s;

var newStudent=  o as string;// Exception casting not possible

Join and Set based operation using IEnumerable

Zip method of List is very interesting and very helpful out of box intersect functions where handy . It ignores the non mapping item from two collection list.

ReadOnly vs Immutable collection

ReadOnly Gotcha's

If we declared a collection readonly then it is just a wrapper around the source collection. Here is a catch when I say readOnly collection is just a wrapper I mean it refer source as a reference. There is a point when external library refer readonly collection at a given instance it holds say 10 values. Later stage in the code base if the source reference collection is updated with 11 values in it and we don't want the external library to consume that , in such case readOnly library introduces a complication. For our rescue we should use Immutable only when we are certain readOnly refers to a source that can change due to some conditional logic.

External Library- Refer ReadOnly -R

• R- refer source collection S holds 10 values
• S- Later in the code we add 11 values which External library shouldn't refer to..
• R- refer source collection S holds 11 values

Efficient Use of Dictionary using custom data type

 Note

The speed of retrieval depends on the quality of the hashing algorithm of the type specified for TKey.

Dictionary generic class provides a mapping from a set of keys to a set of values. Each addition to the dictionary consists of a value and its associated key. Retrieving a value by using its key is very fast, close to O(1), because the Dictionary class is implemented as a hash table.

Performance List.Remove(T) Method is an O(n) operation

List.Remove(T) Method

If type T implements the IEquatable generic interface, the equality comparer is the Equals method of that interface; otherwise, the default equality comparer is Object.Equals.

This method performs a linear search; therefore, this method is an O(n) operation, where n is Count.

Performance List.Item[Int32] Property is O(1) operation

List.Item[i] is O(1) operation

Reason : There is a very large data list and suppose system wants to lookup for 9999 some element in the list. The operation performed to located is one step that is current location+ 9999= 0+9999

Gets or sets the element at the specified index.

C#

public T this[int index] { get; set; }

List accepts null as a valid value for reference types and allows duplicate elements.

This property provides the ability to access a specific element in the collection by using the following syntax: myCollection[index].

Retrieving the value of this property is an O(1) operation; setting the property is also an O(1) operation.

C# Short circuiting vs Non Short Circuiting logical condition

Short Circuit use && just check first condition and decide the outcome whereas & will evaluate all and conditions. Non short circuit may increase cyclomatic complexity.

#csharp Short circuiting logic condition vs Non Short circuiting logic condition

Short Circuit : &&
Non Short Circuit : &
Short Circuit : ||
Non Short Circuit just : |#programming #programmer #Coding #100DaysOfCode #code #CodeNewbie pic.twitter.com/7lJQMQNTgB

— San (@santoshpoojari3) April 19, 2020

How to Use Keywords as Variable Names @csharp

Use Keywords as Variable Names in #csharp var @string= string.Empty;

@string = "We can use keyword string as variable name, cool huh! trick compiler, we know better.."
In case, if you want to use Keywords as variable names (identifiers), then you need to include @ as a prefix for your variable names. For example, @switch is a valid identifier but the switch is not because it's a keyword and having a special meaning for the compiler.