Introduced in the 1977 ANSI M[UMPS] language standard.

This function returns information about whether and where a substring occurs in a string.

Assume that TEXT="ABCDABEFAD"

Reference		Value
SET Y=$FIND(TEXT,"A")		2
SET Y=$FIND(TEXT,"A",2)		6
SET Y=$FIND(TEXT,"A",11)		11
SET Y=$FIND(TEXT,"ABC",1)		4
SET Y=$FIND(TEXT,"ABD")		0
SET Y=$FIND(TEXT,"")		1
SET Y=$FIND(TEXT,"",4)		4
SET T=TEXT SET L=$LENGTH(T)+1 SET Y=$FIND(T,"",L)		0

SET TEXT="ABCATEXTYZ"

Reference		Value
$FIND(TEXT,"A")		2
$FIND(TEXT,"B")		3
$FIND(TEXT,"Z")		0
$FIND(TEXT,"ABC")		4
$FIND(TEXT,"TEXT")		9
$FIND(TEXT,TEXT)		11
$FIND("ABC","ABC")		4
$FIND(TEXT,"A",1)		2
$FIND(TEXT,"A",2)		5
$FIND(TEXT,"A",4)		5
$FIND(TEXT,"A",5)		0
$FIND(TEXT,"A",100)		0
$FIND(TEXT,"")		1
$FIND(TEXT,"",4)		4
$FIND(TEXT,"",10)		10

SET Y="B"

Reference		Value
$FIND(TEXT,Y)		3

SET Z="1.2W",Y="B"

Reference		Value
$FIND(TEXT,Y,Z)		3
$FIND(TEXT,Y,2)		3

Examples with naked references:

$FIND(VALUE,STRING)
SET ^ABC(1,2)="reset naked indicator"
; Naked indicator is now ^ABC(1,
SET ^(3,4)=$FIND(^(5,6),^(7,8))
; 1. fetch ^(5,6) = ^ABC(1,5,6)
; 2. fetch ^(7,8) = ^ABC(1,5,7,8)
; 3. store ^(3,4) = ^ABC(1,5,7,3,4)
; Naked indicator is now: ^ABC(1,5,7,3,

$FIND(VALUE,STRING,FROM)
SET ^ABC(1,2)="reset naked indicator"
; Naked indicator is now ^ABC(1,
SET ^(3,4)=$FIND(^(5,6),^(7,8),^(9,10))
; 1. fetch ^(5,6) = ^ABC(1,5,6)
; 2. fetch ^(7,8) = ^ABC(1,5,7,8)
; 3. fetch ^(9,10) = ^ABC(1,5,7,9,10)
; 4. store ^(3,4) = ^ABC(1,5,7,9,3,4)
; Naked indicator is now: ^ABC(1,5,7,9,3,