InStr Function

Returns the position of the first occurrence of one string within another.

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

Arguments

• start
  Optional. Numeric expression that sets the starting position for each search. The first character position is position 1. If this argument is omitted, search starts at the first character position.

  If the compare argument is specified, a start argument is required.

• 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 this argument is omitted, a binary comparison is performed.

  If this argument is specified, a start argument is required.

Settings

The compare argument can have the following values:

Constant	Value	Description
vbBinaryCompare	0	Perform a binary comparison.
vbTextCompare	1	Perform a textual comparison.

Return Value

The InStr function 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(string1)	0

Remarks

The following examples use InStr to search a string:

Dim MyPos

' This is a binary comparison because the last argument is omitted.
' Returns 3.
MyPos = InStr ("abcdefgh", "c")

' In this binary comparison, the uppercase "C" is not found
' in the lowercase string.
' Returns 0 (not found).
MyPos = InStr ("abcdefgh", "C")

' In this text comparison starting at the first position,
' the uppercase "C" is found in the lowercase string.
' Returns 3.
MyPos = InStr (1, "abcdefgh", "C", vbTextCompare)

Note

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.

Requirements

Version 1

See Also

Reference

InStrRev Function

Change History

Date	History	Reason
September 2010	Modified argument definitions.	Customer feedback.
April 2009	Modified example and start argument definition.	Customer feedback.