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POhow to use Exist in List<string> in C#
 

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  1. POhow to use Exist in List<string> in C#
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    <p>I have to find if string exist in a list to avoid duplicates inserts: Here is example from Microsoft site:</p> <pre><code>using System; using System.Collections.Generic; public class Example { public static void Main() { List&lt;string&gt; dinosaurs = new List&lt;string&gt;(); dinosaurs.Add("Compsognathus"); dinosaurs.Add("Amargasaurus"); dinosaurs.Add("Oviraptor"); dinosaurs.Add("Velociraptor"); dinosaurs.Add("Deinonychus"); dinosaurs.Add("Dilophosaurus"); dinosaurs.Add("Gallimimus"); dinosaurs.Add("Triceratops"); Console.WriteLine(); foreach(string dinosaur in dinosaurs) { Console.WriteLine(dinosaur); } Console.WriteLine("\nTrueForAll(EndsWithSaurus): {0}", dinosaurs.TrueForAll(EndsWithSaurus)); Console.WriteLine("\nFind(EndsWithSaurus): {0}", dinosaurs.Find(EndsWithSaurus)); Console.WriteLine("\nFindLast(EndsWithSaurus): {0}", dinosaurs.FindLast(EndsWithSaurus)); Console.WriteLine("\nFindAll(EndsWithSaurus):"); List&lt;string&gt; sublist = dinosaurs.FindAll(EndsWithSaurus); foreach(string dinosaur in sublist) { Console.WriteLine(dinosaur); } Console.WriteLine( "\n{0} elements removed by RemoveAll(EndsWithSaurus).", dinosaurs.RemoveAll(EndsWithSaurus)); Console.WriteLine("\nList now contains:"); foreach(string dinosaur in dinosaurs) { Console.WriteLine(dinosaur); } Console.WriteLine("\nExists(EndsWithSaurus): {0}", dinosaurs.Exists(EndsWithSaurus)); } // Search predicate returns true if a string ends in "saurus". private static bool EndsWithSaurus(String s) { return s.ToLower().EndsWith("saurus"); } } </code></pre> <p>Is it possible to replace <code>EndsWithSaurus</code> function with lambda expression? Thanks everybody for your input!! Here is a working code: </p> <pre><code> if (dinosaurs.Any(e =&gt; e.EndsWith("saurus"))) Console.WriteLine("saurus exists"); if (dinosaurs.Exists(e =&gt; e.EndsWith("saurus"))) Console.WriteLine("saurus exists"); </code></pre>
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    1. USBalaji Kandasamy
    1. USGenZiy
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      1. VTUpMod
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    1. COTwo remarks for your replacement: 1) to compare, use `==` instead of `=`, which assigns; 2) when the method already returns true, you don't need to compare that value again.
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      1. USHans Kesting
    2. COIf you **only** want to check for existence, a `HashSet<T>` may have value, note
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      1. USMarc Gravell
    3. COYou realize that your two solutions are functionally equivalent, right?
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      1. USD Stanley
 

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