InStr()

Searches for a given occurrence of a string, from the left or the right.

FoundPos := InStr(Haystack, Needle , CaseSensitive := false, StartingPos := 1, Occurrence := 1)

Parameters

Haystack

The string whose content is searched.

Needle

The string to search for.

CaseSensitive

If the parameter CaseSensitive is omitted or false, the search is not case sensitive (the method of insensitivity depends on StringCaseSense); otherwise, the case must match exactly.

StartingPos

If StartingPos is omitted, it defaults to 1 (the beginning of Haystack). Otherwise, specify 2 to start at the second character, 3 to start at the third, and so on.

If StartingPos is negative, the search is conducted in reverse (right-to-left), starting at that position from the right. For example, -1 starts at the last character. If StartingPos is 0 or beyond the length of Haystack, 0 is returned.

Regardless of the value of StartingPos, the return value is always relative to the first character of Haystack. For example, the position of "abc" in "123abc789" is always 4.

Occurrence

If Occurrence is omitted, it defaults to the first match of the Needle in Haystack. Specify 2 for Occurrence to return the position of the second match, 3 for the third match, etc.

Return Value

This function returns the position of an occurrence of the string Needle in the string Haystack. Position 1 is the first character; this is because 0 is synonymous with "false", making it an intuitive "not found" indicator.

Remarks

RegExMatch can be used to search for a pattern (regular expression) within a string, making it much more flexible than InStr(). However, InStr() is generally faster than RegExMatch() when searching for a simple substring.

InStr() searches only up to the first binary zero (null-terminator), whereas RegExMatch() searches the entire length of the string even if it includes binary zero.

Related

RegExMatch, StringCaseSense, Value is Type

Example

; Example 1
MsgBox % InStr("123abc789","abc") ; Returns 4

; Example 2
Haystack := "The Quick Brown Fox Jumps Over the Lazy Dog"
Needle := "Fox"
If InStr(Haystack, Needle)
  MsgBox, The string was found.
Else
  MsgBox, The string was not found.

; Example 3
Haystack := "The Quick Brown Fox Jumps Over the Lazy Dog"
Needle := "the"
MsgBox % InStr(Haystack, Needle, false, 1, 2) ; case insensitive search, return start position of second occurence
MsgBox % InStr(Haystack, Needle, true) ; case sensitive search, return start position of first occurence, same result as above