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

This function returns information about the length of a string.

Reference		Value
$LENGTH("ABC")		3
$LENGTH("ABCD354")		7

SET X="ABCD"

Reference		Value
$LENGTH(X)		4
$LENGTH("")		0 (zero)

SET X=""

Reference		Value
$LENGTH(X)		0 (zero)

SET X="ABC"

Reference		Value
$LENGTH(X)		3

SET X="123456789"

Reference		Value
$LENGTH(X)		9

SET X=""

Reference		Value
$LENGTH(X)		0

Addition in the 1990 ANSI M[UMPS] language standard (count pieces separated by value of second parameter):

Reference		Value
$LENGTH("A.B.C",".")		3
$LENGTH("A.B.C","-")		1
$LENGTH("A-A-A-A","A-")		4, not 3.5

The value of $LENGTH("abababaaba","aba") is seemingly open to interpretation, after all, the string "abababaaba"can be segmented in various ways, and the function value would vary with the interpretation

• aba b aba aba, which would justify a value of 4
• ab aba ba aba, which would justify a value of 3

Because the language standard stipulates that in all cases where a choice exists, strict left-to-right evaluation prevails, the second interpretation is the one that is endorsed by the language standard.

Examples with naked references:

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

$LENGTH(VALUE,SUBSTR)
SET ^ABC(1,2)="reset naked indicator"
; Naked indicator is now ^ABC(1,
SET ^(3,4)=$LENGTH(^(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,

This document is © Ed de Moel, 1995-2005.
It is part of a book by Ed de Moel that is published under the title "M[UMPS] by Example" (ISBN 0-918118-42-5).
Printed copies of the book are no longer available.

This document describes the various operators that are defined in the M[UMPS] language standard (ANSI X11.1, ISO 11756).

The information in this document is NOT authoritative and subject to be modified at any moment.
Please consult the appropriate (draft) language standard for an authoritative definition.

In this document, information is included that will appear in future standards.
The MDC cannot guarantee that these 'next' standards will indeed appear.