LTrim, RTrim

The L stands for Left—the left trim method removes spaces from the left of a String. RTrim removes from the right side of String data.

Similar to TrimStart, and TrimEnd, these 2 VB.NET functions are familiar and may be useful still. They call into TrimStart and TrimEnd.

LTrim

In this example, we declare a String literal with 3 spaces at its start. Then, we pass the variable that points to that String literal to the LTrim function.

Module Module1
    Sub Main()
        Dim value1 As String = "   abc"
        Dim value2 As String = LTrim(value1)
        Console.WriteLine("[{0}]", value2)
    End Sub
End Module
[abc]

RTrim

A String literal with several trailing spaces is declared and the value1 variable points to it. When this variable is passed to RTrim, another String is returned.

Module Module1
    Sub Main()
        Dim value1 As String = "xyz    "
        Dim value2 As String = RTrim(value1)
        Console.WriteLine("[{0}]", value2)
    End Sub
End Module
[xyz]

How is the LTrim function implemented? To investigate, I opened the Microsoft.VisualBasic.dll file with IL Disassembler. I found that, internally, LTrim calls TrimStart.

Internally, RTrim simply calls TrimEnd on the String type. TrimEnd is a form of Trim that only acts on the trailing (right-side) characters.

We looked at the LTrim function (and its implementation) in VB.NET. This function may be convenient and familiar—but it simply invokes TrimStart.