InStr Function
Description
Returns a Variant (Long) specifying the position of the first occurrence of one string within another.
Syntax
InStr([start, ]string1, string2[, compare])
The InStr function syntax has these arguments
| Part | Description |
|
| start | Optional. Numeric expression that sets the starting position for each search. If omitted, search begins at the first character position. If start contains Null, an error occurs. The start argument is required if compare is specified. |
| string1 | Required. String expression being searched. |
| string2 | Required. String expression sought. |
| compare | Optional. Specifies the type of string comparison. The compare argument can be omitted, or it can be 0, 1 or 2. Specify 0 (default) to perform a binary comparison. Specify 1 to perform a textual, noncase-sensitive comparison. For Microsoft Access only, specify 2 to perform a comparison based on information contained in your database. If compare is Null, an error occurs. If compare is omitted, the Option Compare setting determines the type of comparison. |
Return Values
| If | InStr returns |
|
| string1 is zero-length | 0 |
| string1 is Null | Null |
| string2 is zero-length | start |
| string2 is Null | Null |
| string2 is not found | 0 |
| string2 is found within string1 | Position at which match is found |
| start > string2 | 0 |
Remarks
The InStrB function is used with byte data contained in a string. Instead of returning the character position of the first occurrence of one string within another, InStrB returns the byte position.
See Also
Option Compare statement, StrComp function.
Example
This example uses the InStr function to return the position of the first occurrence of one string within another.
Dim SearchString, SearchChar, MyPos
SearchString ="XXpXXpXXPXXP" ' String to search in.
SearchChar = "P" ' Search for "P".
' A textual comparison starting at position 4. Returns 6.
MyPos = Instr(4, SearchString, SearchChar, 1)
' A binary comparison starting at position 1. Returns 9.
MyPos = Instr(1, SearchString, SearchChar, 0)
' Comparison is binary by default (last argument is omitted).
MyPos = Instr(SearchString, SearchChar) ' Returns 9.
MyPos = Instr(1, SearchString, "W") ' Returns 0.