string.substring vs string.take

Question

If you want to only take a part of a string, the substring method is mostly used. This has a drawback that you must first test on the length of the string to avoid errors. For example you want to save data into a database, and want to cut off a value to the first 20 characters.

If you do temp.substring(0,20) but temp only holds 10 chars, an exception is thrown.

There are 2 solutions that I see :

1. test on the length, and do the substring if needed

2. use the extension method Take

       string temp = "1234567890";     var data= new string( temp.Take(20).ToArray());     --> data now holds "1234657890" 

Is there any disadvantage in terms of speed or memory use , when one uses the Take method. The benefit is that you do not have to write all those if statements.

Answer 1

If you find yourself doing this a lot, why not write an extension method?

For example:

using System;  namespace Demo {     public static class Program     {         public static void Main(string[] args)         {             Console.WriteLine("123456789".Left(5));             Console.WriteLine("123456789".Left(15));         }     }      public static class StringExt     {         public static string Left(this string @this, int count)         {             if (@this.Length <= count)             {                 return @this;             }             else             {                 return @this.Substring(0, count);             }         }     } }