Get Substring Position Method

The Get Substring Position method returns the position of the first occurrence of a substring that resides in another string. It can also return the following values:

• Returns a zero in the following situations:

• The value in the start argument is greater than the length of the value in the string2 argument.

• The string1 argument contains a null string.

• The string2 argument is not found.

• If the string1 argument or the string2 argument contains a null variant, then it returns a null variant.

• If the string2 argument contains a null string (""), then it returns the value of the start argument.

Format A

InStr([start,] string1, string2)

InStr(start, string1, string2[, compare])

Arguments can be of any type. This method converts them to strings.

The following table describes the arguments that you can use with this method.

Argument	Description
start	An integer that identifies a position in the string that the string1 argument identifies. This position is the starting position, with the first character in the string as 1. If you do not specify a value for the start argument, then this method starts at the beginning of the string.
string1	The string that includes the substring.
string2	The substring.
compare	You can use one of the following values: 0. Perform a search that is case-sensitive according to the ANSI character set sequence. 1. Perform a search that is not case-sensitive according to the relative order of characters as determined by the country code setting for your computer. If you do not include the compare argument, then this method uses the module level default that the Set String Comparison method sets. For more information, see Set String Comparison Method.

Example

The following example creates a random string of characters, and then uses the Get Substring Position method to find the position of a single character in that string:

Sub Button_Click
   Dim x as Integer
   Dim y
   Dim str1 as String
   Dim str2 as String
   Dim letter as String
   Dim randomvalue
   Dim upper, lower
   Dim position as Integer
   Dim msgtext, newline
   upper = Asc("z")
   lower = Asc("a")
   newline = Chr(10)
   Randomize
   For x = 1 to 26
      randomvalue = Int(((upper - (lower + 1)) * Rnd) + lower)
      letter = Chr(randomvalue)
      str1 = str1 & letter
'Need to waste time here for fast processors
      For y = 1 to 1000
      Next y
   Next x
   str2 = "i"
   position = InStr(str1,str2)
   If position then
      msgtext = "The position of " & str2 & " is: " _
      & position & newline & "in string: " & str1
   Else
      msgtext = "The letter: " & str2 & " was not found in: " _
      & newline
      msgtext = msgtext & str1
   End If
End Sub