Server Side Programming Articles - Page 2436 of 2650

Get the maximum value from a sequence using the Max() method.Let’s say the following is our list.List list = new List { 200, 400, 600, 800, 1000, 1200, 1400, 1600, 1800, 2000 };Use the Max() method to get the largest element.list.AsQueryable().Max();Example Live Demousing System; using System.Collections.Generic; using System.Linq; class Demo {    static void Main() {       List list = new List { 200, 400, 600, 800, 1000, 1200, 1400, 1600, 1800, 2000 };       foreach(long ele in list)       Console.WriteLine(ele);       // getting largest element       long max_num = list.AsQueryable().Max();       Console.WriteLine("Largest number = {0}", max_num);    } }Output200 400 600 800 1000 1200 1400 1600 1800 2000 Largest number = 2000

AsQueryable() method is used to get an IQueryable reference.Let us see an example to find sum of integer values.Firstly, set an integer array.var arr = new int[] { 100, 200, 300, 400 };Now to find the sum, use the Queryable Sum() and AsQueryable() method.Queryable.Sum(arr.AsQueryable());The following is the complete code.Example Live Demousing System; using System.Linq; class Demo {    static void Main() {       var arr = new int[] { 100, 200, 300, 400 };       int res = Queryable.Sum(arr.AsQueryable());       Console.WriteLine("Sum: "+res);    } }OutputSum: 1000

The method matches instances of a pattern and is used to extract value based on a pattern.Let us see hoe to check for a valid URL.For that, pass the regex expression in the Matches method.MatchCollection mc = Regex.Matches(text, expr);Above, the expr is our expression that we have set to check for valid URL."^(http|http(s)?://)?([\w-]+\.)+[\w-]+[.com|.in|.org]+(\[\?%&=]*)?”The text we have set to check is a URL i.e.https://demo.comLet us see the complete code.Example Live Demousing System; using System.Text.RegularExpressions; namespace Demo {    class Program {       private static void showMatch(string text, string expr) {          MatchCollection mc = Regex.Matches(text, expr);   ... Read More

Use the FirstorDefault() method to return the first element of a sequence or a default value if element isn’t there.The following is our empty list −List val = new List { };Now, we cannot display the first element, since it is an empty collection. For that, use the FirstorDefault() method to display the default value.val.AsQueryable().FirstOrDefault();The following is the complete example.Example Live Demousing System; using System.Collections.Generic; using System.Linq; class Demo {    static void Main() {       List val = new List { };       double d = val.AsQueryable().FirstOrDefault();       Console.WriteLine("Default Value = "+d);     ... Read More

Find common elements between two arrays using the Intersect() method.The following are our arrays −int[] val1 = { 15, 20, 40, 60, 75, 90 }; int[] val2 = { 17, 25, 35, 55, 75, 90 };To perform intersection.val1.AsQueryable().Intersect(val2);Let us see the entire example.Example Live Demousing System; using System.Collections.Generic; using System.Linq; class Demo {    static void Main() {       int[] val1 = { 15, 20, 40, 60, 75, 90 };       int[] val2 = { 17, 25, 35, 55, 75, 90 };       IEnumerable res = val1.AsQueryable().Intersect(val2);       Console.WriteLine("Intersection of both the lists...");       foreach (int a in res)       Console.WriteLine(a);    } }OutputIntersection of both the lists... 75 90

To cast a specific type to its IEnumerable equivalent, use the AsEnumerable() method. It is an extension method.The following is our array −int[] arr = new int[5]; arr[0] = 10; arr[1] = 20; arr[2] = 30; arr[3] = 40; arr[4] = 50;Now, get the IEnumerable equivalent.arr.AsEnumerable();Example Live Demousing System; using System.Linq; class Demo {    static void Main() {       int[] arr = new int[5];       arr[0] = 10;       arr[1] = 20;       arr[2] = 30;       arr[3] = 40;       arr[4] = 50;       var res = arr.AsEnumerable();       foreach (var ele in res) {          Console.WriteLine(ele);       }    } }Output10 20 30 40 50

The following are our strings in a list −List list = new List { "keyboard", "mouse", "joystick", "monitor" };To use the first 3 letters, use substring method and use it under the Linq Select method.IEnumerable res = list.AsQueryable() .Cast() .Select(str => str.Substring(0, 3));Example Live Demousing System; using System.Linq; using System.Collections.Generic; class Demo {    static void Main() {       List list = new List { "keyboard", "mouse", "joystick", "monitor" };       // getting first 3 letters from every string       IEnumerable res = list.AsQueryable() .Cast() .Select(str =>       str.Substring(0,3));       foreach (string str in res) {          Console.WriteLine(str);       }    } }Outputkey mou joy mon

To handle empty collections, use the DefaultIfEmpty() method in C#.If an array is empty, then using this method will show the default method instead of displaying an error.Let’s say we have an empty list.List myList = new List();Now, use DefaultIfEmpty() method to display the default value.myList.DefaultIfEmpty();Example Live Demousing System; using System.Linq; using System.Collections.Generic; class Demo {    static void Main() {       List myList = new List();       var res = myList.DefaultIfEmpty();       foreach (var a in res) {          Console.WriteLine(a);       }    } }Output0

Set a sequence and add elements.List ID = new List { 120, 111, 250, 111, 120, 300, 399, 450 };Use Distinct() method to get distinct element from the above list.IEnumerable res = ID.AsQueryable().Distinct();Let us see the complete code.Example Live Demousing System; using System.Linq; using System.Collections.Generic; class Demo {    static void Main() {       List ID = new List { 120, 111, 250, 111, 120, 300, 399, 450 };       // get distinct elements       IEnumerable res = ID.AsQueryable().Distinct();       foreach (int arr in res) {          Console.WriteLine(arr);       }    } }Output120 111 250 300 399 450

The following is our Dictionary with some elements −Dictionary d = new Dictionary() {    {1,"Electronics"},    {2, "Clothing"},    {3,"Toys"},    {4,"Footwear"},    {5, "Accessories"} };Now to display the first element, set the key like this.d[1];The above displays the first element.Example Live Demousing System; using System.Collections.Generic; public class Program {    public static void Main() {       Dictionary d = new Dictionary() {          {1,"Electronics"},          {2, "Clothing"},          {3,"Toys"},          {4,"Footwear"},          {5, "Accessories"}       };       foreach (KeyValuePair ele in d) {          Console.WriteLine("Key = {0}, Value = {1}", ele.Key, ele.Value);       }       Console.WriteLine("First element: "+d[1]);    } }OutputKey = 1, Value = Electronics Key = 2, Value = Clothing Key = 3, Value = Toys Key = 4, Value = Footwear Key = 5, Value = Accessories First element: Electronics