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.NET equivalent of the old vb left(string, length) function

Tags:

c#

.net

vb.net

As a non-.NET programmer I'm looking for the .NET equivalent of the old Visual Basic function left(string, length). It was lazy in that it worked for any length string. As expected, left("foobar", 3) = "foo" while, most helpfully, left("f", 3) = "f".

In .NET string.Substring(index, length) throws exceptions for everything out of range. In Java I always had the Apache-Commons lang.StringUtils handy. In Google I don't get very far searching for string functions.


@Noldorin - Wow, thank you for your VB.NET extensions! My first encounter, although it took me several seconds to do the same in C#:

public static class Utils {     public static string Left(this string str, int length)     {         return str.Substring(0, Math.Min(length, str.Length));     } } 

Note the static class and method as well as the this keyword. Yes, they are as simple to invoke as "foobar".Left(3). See also C# extensions on MSDN.

like image 831
Josh Avatar asked May 09 '09 21:05

Josh


People also ask

What does left do in Visual Basic?

The VBA LEFT function is listed under the text category of VBA functions. When you use it in a VBA code, it returns a sub-string from a string from the starting position. In simple words, you can extract a number of characters from a string from its starting (which is the left side).


1 Answers

Here's an extension method that will do the job.

<System.Runtime.CompilerServices.Extension()> _ Public Function Left(ByVal str As String, ByVal length As Integer) As String     Return str.Substring(0, Math.Min(str.Length, length)) End Function 

This means you can use it just like the old VB Left function (i.e. Left("foobar", 3) ) or using the newer VB.NET syntax, i.e.

Dim foo = "f".Left(3) ' foo = "f" Dim bar = "bar123".Left(3) ' bar = "bar" 
like image 76
Noldorin Avatar answered Sep 21 '22 12:09

Noldorin