Returns the position of the first occurrence of one string within another.
InStr([Start, ]string1, string2[, compare])
The InStr yntax 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 searched for. |
| compare | Optional. Numeric value indicating the kind of comparison to use when evaluating substrings. See Settings section for values. If omitted, a binary comparison is performed. |
The compare argument can have the following values:
| Constant | Value | Description |
|---|---|---|
| vbBinaryCompare | 0 | Perform a binary comparison. |
| vbTextCompare | 1 | Perform a textual comparison. |
| vbDatabaseCompare | 2 | Perform a comparison based upon information contained in the database where the comparison is to be performed. |
The Instr returns the following 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 > Len(string2) | 0 |
Note The InStrBis 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.