Microsoft® Visual Basic® Scripting Edition

InStr Function

Description

Returns 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 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 String expression being searched.
string2 String expression sought.
compare Specifies the type of string comparison. The compare argument can be omitted, it can be 0 or 1. Specify 0 (default) to perform a binary comparison. Specify 1 to perform a textual, case-insensitive comparison. If compare is Null, an error occurs. The start argument is required if compare is specified. If compare is omitted, a binary comparison is performed.

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

Note Another function (InStrB) is provided for use 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.

Part	Description
start	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	String expression being searched.
string2	String expression sought.
compare	Specifies the type of string comparison. The compare argument can be omitted, it can be 0 or 1. Specify 0 (default) to perform a binary comparison. Specify 1 to perform a textual, case-insensitive comparison. If compare is Null, an error occurs. The start argument is required if compare is specified. If compare is omitted, a binary comparison is performed.

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


Note Another function (InStrB) is provided for use 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.