VBS TUTORIAL: function-INSTR function _vbs

InStr function

Returns the position of the first occurrence of a string in another string.

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

Parameters

Start

Options available. A numeric expression that sets the starting position for each search. If omitted, the search begins at the position of the first character. If start contains Null, an error occurs. If you have specified compare, you must have the start argument.

String1

Required option. The string expression that accepts the search.

string2

Required option. The string expression to search for.

Compare

Options available. Indicates the numeric value of the comparison type to use when calculating the substring. For numeric values, see the "Settings" section. If omitted, a binary comparison is performed.

Set up

The compare parameter can have the following values:

Constants	value	Description
Vbbinarycompare	0	Performs a binary comparison.
vbTextCompare	1	Performs a text comparison.

return value

The InStr function returns the following values:

if	InStr return
String1 is zero length	0
String1 is Null	Null
string2 is zero length	Start
String2 is Null	Null
String2 didn't find it.	0
Find string2 in string1.	Find the location of the matching string
Start > Len (string2)	0

Description

The following example uses InStr to search for strings:

Dim SearchString, SearchChar, MyPosSearchString ="XXpXXpXXPXXP"   ' String to search in.SearchChar = "P"   ' Search for "P".MyPos = Instr(4, SearchString, SearchChar, 1)' A textual comparison starting at position 4. Returns 6.MyPos = Instr(1, SearchString, SearchChar, 0)' A binary comparison starting at position 1. Returns 9.    MyPos = Instr(SearchString, SearchChar)' Comparison is binary by default (last argument is omitted). Returns 9.MyPos = Instr(1, SearchString, "W")' A binary comparison starting at position 1. Returns 0 ("W" is not found).

Attention The InStrB function uses the byte data contained in the string, so InStrB returns not the character position where the string first appears in another string, but the byte position.