VB.NET - String PadRight and PadLeft

PadRight, PadLeft. Padding changes the length of VB.NET Strings. It adds extra characters to the right or left of the String data.

Function details. PadLeft adds spaces to the left side—and PadRight adds to the right. Both also support other padding characters.

String Trim

PadLeft example. This program creates an array filled with 3 Strings. It then loops over these Strings. Each String has up to five characters of padding added to the left.

And This new String returned by PadLeft is then passed to Console.WriteLine.

Info PadLeft does not modify the String data. Instead it creates a modified String in new memory.

So This means the String Dim you call it on—in this program "w"—is not modified in any way.

For

Module Module1
    Sub Main()
        Dim words() As String = {"A", "Net", "Perls"}
        ' Loop over words.
        For Each w As String In words
            Console.WriteLine(w.PadLeft(5))
        Next
    End Sub
End Module    A
  Net
Perls

PadRight example. The PadLeft Function is paired with PadRight. Here we add complexity by using a Dictionary collection. For keys we use Strings. For values we use Integers.

Dictionary

Integer

Here We loop over the Dictionary and apply padding to the Key. For the value we first convert the Integer to a String.

KeyValuePair

Module Module1
    Sub Main()
        ' Create Dictionary.
        Dim dict As Dictionary(Of String, Integer) = New Dictionary(Of String, Integer)
        dict.Add("Cat", 5)
        dict.Add("Mouse", 1)
        dict.Add("Leopard", 9)
        dict.Add("Asp", 10)

        ' Loop over pairs.
        For Each pair As KeyValuePair(Of String, Integer) In dict
            ' Pad right of key.
            Console.Write(pair.Key.PadRight(10))
            ' Pad left of value.
            Console.WriteLine(pair.Value.ToString().PadLeft(2))
        Next
    End Sub
End ModuleCat        5
Mouse      1
Leopard    9
Asp       10

Example 3. PadLeft and PadRight can add any Char value you like. In this program we use a period as the second argument to PadRight. And for PadLeft we pass a hash sign.

And The output String contains padding with these special characters, not spaces.

Module Module1
    Sub Main()
        ' Pad with . and #
        Console.Write("Sam".PadRight(10, "."c))
        Console.WriteLine("28173".PadLeft(6, "#"c))
        ' Next line.
        Console.Write("Mark".PadRight(10, "."c))
        Console.WriteLine("137".PadLeft(6, "#"c))
    End Sub
End ModuleSam.......#28173
Mark......137

Summary. Text-based display of data is common. It is an easy way to format tables in console programs. PadLeft and PadRight help in code that displays numeric data.