VB.Net Tutorial/Data Type/String Find

Demonstrating StartsWith and EndsWith methods

<source lang="vbnet">Module Tester

  Sub Main()
     Dim strings As String()
     Dim output As String = ""
     Dim i As Integer
     Dim quotes As Char = ChrW(34)
     strings = New String() {"started", "starting", _
        "ended", "ending"}
     For i = 0 To strings.GetUpperBound(0)
        If strings(i).StartsWith("st") Then
           Console.WriteLine(" starts with st")
        End If
     Next
     For i = 0 To strings.GetUpperBound(0)
        If strings(i).EndsWith("ed") Then
           Console.WriteLine(" ends with ed" )
        End If
     Next
  End Sub " Main

End Module</source>

starts with st
 starts with st
 ends with ed
 ends with ed

Return the index of the string

<source lang="vbnet">Option Strict On

Imports System
Class Tester
    Public Shared Sub Main( )
        Dim s1 As String = "abcd"
        Dim s2 As String = "ABCD"
        Dim s3 As String = "AAAAs "
        s3 = s3 & "development"
        Console.WriteLine("s3: {0}", s3)
        
        Console.Write("The first occurrence of a ")
        Console.WriteLine(s3.IndexOf("a"))

    End Sub "Main
End Class "Tester</source>

s3: AAAAs development
The first occurrence of a -1

String Index of any

<source lang="vbnet">public class Test

  public Shared Sub Main
              Dim s1 As New String("Greeting")
       Console.WriteLine(s1.IndexOfAny("tin"))
  End Sub

End class</source>

4

Use IndexOfAny to find first occurrence of character in array

<source lang="vbnet">Module Tester

  Sub Main()
     Dim letters As String = "abcdefghijklmabcdefghijklm"
     Dim searchLetters As Char() = New Char() {"c"c, "a"c, "$"c}
     Console.WriteLine("First occurrence of ""c""," & _
       " ""a"" or ""$"" is located at " & _
       letters.IndexOfAny(searchLetters))
     Console.WriteLine("First occurrence of ""c"", ""a"" or " & _
        """$"" is located at " & _
        letters.IndexOfAny(searchLetters, 7))
     Console.WriteLine("First occurrence of ""c"", ""a"" or " & _
        """$"" is located at " & _
        letters.IndexOfAny(searchLetters, 20, 5))
     
     End Sub 

End Module</source>

First occurrence of "c", "a" or "$" is located at 0
First occurrence of "c", "a" or "$" is located at 13
First occurrence of "c", "a" or "$" is located at -1

Use IndexOf to locate a substring in a string

<source lang="vbnet">Module Tester

  Sub Main()
     Dim letters As String = "abcdefghijklmabcdefghijklm"
     Dim searchLetters As Char() = New Char() {"c"c, "a"c, "$"c}
     
     Console.WriteLine(letters.IndexOf("def"))
     Console.WriteLine(letters.IndexOf("def", 7))
     Console.WriteLine(letters.IndexOf("hello", 5, 15))
  End Sub 

End Module</source>

3
16
-1

Use LastIndexOfAny to find first occurrence of character in array

<source lang="vbnet">Module Tester

  Sub Main()
     Dim letters As String = "abcdefghijklmabcdefghijklm"
     Dim searchLetters As Char() = New Char() {"c"c, "a"c, "$"c}
     Console.WriteLine("Last occurrence of ""c""," & _
        " ""a"" or ""$"" is located at " & _
        letters.LastIndexOfAny(searchLetters))
     Console.WriteLine("Last occurrence of ""c"", ""a"" or " & _
        """$"" is located at " & _
        letters.LastIndexOfAny(searchLetters, 1))
     Console.WriteLine("Last occurrence of ""c"", ""a"" or " & _
        """$"" is located at " & _
        letters.LastIndexOfAny(searchLetters, 25, 5))
     
     End Sub 

End Module</source>

Last occurrence of "c", "a" or "$" is located at 15
Last occurrence of "c", "a" or "$" is located at 0
Last occurrence of "c", "a" or "$" is located at -1

Use LastIndexOf to find a substring in a string

<source lang="vbnet">Module Tester

  Sub Main()
     Dim letters As String = "abcdefghijklmabcdefghijklm"
     Dim searchLetters As Char() = New Char() {"c"c, "a"c, "$"c}
     Console.WriteLine(letters.LastIndexOf("def"))
     Console.WriteLine(letters.LastIndexOf("def", 25))
     Console.WriteLine(letters.LastIndexOf("hello", 20, 15))   
  End Sub 

End Module</source>

16
16
-1