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{{Built-in|Not|~}} is a | {{Built-in|Not|~}} is a [[monadic]] [[scalar function]] that returns the [[wikipedia:Negation|logical negation]] of a [[Boolean]] argument—that is, 0 if the argument is 1 and 1 if it is 0. In some languages, such as [[J]], it is extended so that Not <source lang=apl inline>x</source> is equivalent to <source lang=apl inline>1-x</source> while in others, such as [[K]], it is extended so that Not <source lang=apl inline>x</source> is equivalent to <source lang=apl inline>0=x</source>. | ||
== Examples == | == Examples == | ||
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== History == | == History == | ||
[[A Programming Language]] negates arrays using an overbar symbol like <math>\overline{p}</math>, matching a convention sometimes used in mathematics. In [[APL\360]] the current symbol <source lang=apl inline>~</source> was chosen, also due to its use in mathematics. Mathematical usage has arguably diverged from APL in this respect, as the negation of a variable <math>p</math> is now more often written <math>\neg p</math> | [[A Programming Language]] negates arrays using an overbar symbol like <math>\overline{p}</math>, matching a convention sometimes used in mathematics. In [[APL\360]] the current symbol <source lang=apl inline>~</source> was chosen, also due to its use in mathematics. Mathematical usage has arguably diverged from APL in this respect, as the negation of a variable <math>p</math> is now more often written <math>\neg p</math> when a prefix operator is desired. | ||
The arithmetic extension <source lang=apl inline>~x</source> {{←→}} <source lang=apl inline>1-x</source> was introduced to the array langauge family by [[J]]. For arguments in the interval <math>[0,1]</math> this extension may be seen as a probabilistic interpretation of negation. | The arithmetic extension <source lang=apl inline>~x</source> {{←→}} <source lang=apl inline>1-x</source> was introduced to the array langauge family by [[J]]. For arguments in the interval <math>[0,1]</math> this extension may be seen as a probabilistic interpretation of negation. | ||
== Extensions == | |||
{| class=wikitable | |||
! Extension !! Languages | |||
|- | |||
| None || [[APL\360]], [[APL2]], [[APLX]], [[SHARP APL]], [[Dyalog APL]], [[GNU APL]], [[ngn/apl]], [[dzaima/APL]] | |||
|- | |||
| <source lang=apl inline>1-⍵</source> || [[J]] | |||
|- | |||
| <source lang=apl inline>0≠⍵</source> || [[K]] | |||
|} | |||
== See also == | |||
* [[Negate]] | |||
* [[Nor]] | |||
* [[Nand]] | |||
* [[Not Equal to]] | |||
* [[Not Match]] | |||
== External links == | == External links == | ||
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=== Documentation === | === Documentation === | ||
* [http://help.dyalog.com/latest/ | * [http://help.dyalog.com/latest/index.htm#Language/Primitive%20Functions/Not.htm Dyalog] | ||
* [http://microapl.com/apl_help/ch_020_020_400.htm APLX] | * [http://microapl.com/apl_help/ch_020_020_400.htm APLX] | ||
* J [https://www.jsoftware.com/help/dictionary/d121.htm Dictionary], [https://code.jsoftware.com/wiki/Vocabulary/minusdot NuVoc] | * J [https://www.jsoftware.com/help/dictionary/d121.htm Dictionary], [https://code.jsoftware.com/wiki/Vocabulary/minusdot NuVoc] | ||
{{APL built-ins}} | {{APL built-ins}}[[Category:Primitive functions]][[Category:Scalar monadic functions]] |
Revision as of 06:58, 9 July 2020
~
|
Not (~
) is a monadic scalar function that returns the logical negation of a Boolean argument—that is, 0 if the argument is 1 and 1 if it is 0. In some languages, such as J, it is extended so that Not x
is equivalent to 1-x
while in others, such as K, it is extended so that Not x
is equivalent to 0=x
.
Examples
~ 0 1 1 0 1 1 0 0 1 0
Attempting to negate a non-Boolean argument usually results in a DOMAIN ERROR. In some languages it may instead subtract the argument from one.
~ 0 0.5 1 DOMAIN ERROR ~0 0.5 1 ∧
Properties
Not is the only Boolean function of a single argument which depends on that argument (it is not constant) and is not trivial (the same as Identity). Not is its own Inverse.
History
A Programming Language negates arrays using an overbar symbol like , matching a convention sometimes used in mathematics. In APL\360 the current symbol ~
was chosen, also due to its use in mathematics. Mathematical usage has arguably diverged from APL in this respect, as the negation of a variable is now more often written when a prefix operator is desired.
The arithmetic extension ~x
1-x
was introduced to the array langauge family by J. For arguments in the interval this extension may be seen as a probabilistic interpretation of negation.
Extensions
Extension | Languages |
---|---|
None | APL\360, APL2, APLX, SHARP APL, Dyalog APL, GNU APL, ngn/apl, dzaima/APL |
1-⍵ |
J |
0≠⍵ |
K |
See also
External links
Lessons
Documentation