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Left Hand Pointer

Not Operator

M[UMPS] by Example

Right Hand Pointer

Logical unary operator 'not' (')

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

Reference   Value
'12345   0 (false)
'0   1 (true)
'"Apples"   1 (true)

The logical or Boolean value of X:

Reference   Value
''X   0 or 1

The exclusive or of two values:

Reference   Value
'X'='Y   X xor Y

This operator can also be used to modify the meaning of other operators:

'= is not equal to
'> is not greater than, i.e. is less than or equal to
'< is not less than, i.e. is greater than or equal to
'? does not match the pattern
'[ does not contain
'] does not follow
'& not and
'! not or

Added in 1995:
']] does not collate after

To be added in a future standard:
'<= is not less than or equal to, i.e. is greater than
'>= is not greater than or equal to, i.e. is less than
']= does not follow and is not equal to
']]= does not collate after and is not equal to
'!! not exclusive or

Button for 1977 Button for 1984 Button for 1990 Button for 1995 Button for MDC Button for notes Button for examples

Copyright © Standard Documents; 1977-2017 MUMPS Development Committee;
Copyright © Examples: 1995-2017 Ed de Moel;
Copyright © Annotations: 2003-2017 Jacquard Systems Research.

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

Some specifications are "approved for inclusion in a future standard". Note that the MUMPS Development Committee cannot guarantee that such future standards will indeed be published.

This page most recently updated on 12-Sep-2014, 14:15:08 .

For comments, contact Ed de Moel (demoel@jacquardsystems.com)