isNull: Difference between revisions

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Which null type the item has to be equal to depends on the type of game entity tested:
Which null type the item has to be equal to depends on the type of game entity tested:


{{{!}} class{{=}}"wikitable" style{{=}}"text-align: center"
{{{!}} class="wikitable" style="text-align: center"
! [[:Category:Data Types|Type]]
! [[:Category:Data Types|Type]]
{{!}} [[Object]]
{{!}} [[Object]]
Line 37: Line 37:
{{!}} [[Location]]
{{!}} [[Location]]
{{!}} [[Task]]
{{!}} [[Task]]
{{!}} [[Script]]
{{!}} [[Script Handle|Script]]
{{!}} [[Config]]
{{!}} [[Config]]
{{!}} [[Diary Record]]
{{!}} [[Diary Record]]
{{!}} [[Team Member]]
{{!}}-
{{!}}-
! Null value
! Null value
Line 51: Line 52:
{{!}} [[configNull]]
{{!}} [[configNull]]
{{!}} [[diaryRecordNull]]
{{!}} [[diaryRecordNull]]
{{!}}- style{{=}}"font-size: .85em"
{{!}} [[teamMemberNull]]
{{!}}- style="font-size: .85em"
! Since
! Since
{{!}} {{GVI|ofp|1.00}}
{{!}} colspan="2" {{!}} {{GVI|ofp|1.00}}
{{!}} {{GVI|ofp|1.00}}
{{!}} colspan="2" {{!}} {{GVI|arma1|1.00}}
{{!}} {{GVI|arma1|1.00}}
{{!}} colspan="2" {{!}} {{GVI|arma2|1.00}}
{{!}} {{GVI|arma1|1.00}}
{{!}} {{GVI|arma2|1.00}}
{{!}} {{GVI|arma2|1.00}}
{{!}} {{GVI|arma3|1.30}}
{{!}} {{GVI|arma3|1.30}}
{{!}} {{GVI|arma3|1.54}}
{{!}} {{GVI|arma3|1.54}}
{{!}} {{GVI|arma3|2.00}}  
{{!}} {{GVI|arma3|2.00}}
{{!}} {{GVI|arma3|2.10}}
{{!}}}
{{!}}}


{{Feature | important | A test via {{=}}{{=}} does '''not''' work, because a null value is not equal to anything, not even itself ([[configNull]] being the exception).
{{Feature|important|2= A test ''via'' [[a == b|==]] does '''not''' work because a null value is not equal to anything, not even itself ([[configNull]] being the exception).
See also [[isEqualTo]].}}
See also [[isEqualTo]].}}
|pr= [[teamMemberNull]] for [[Team Member]] type is '''not''' supported '''before Arma 3 v2.10.149569'''. Use {{ic|[[private]] _isNull {{=}} _teamMember [[isEqualTo]] [[teamMemberNull]]}} instead.


|s1= [[isNull]] entity
|s1= [[isNull]] entity


|p1= entity: [[Object]], [[Control]], [[Display]], [[Group]], [[Location]], [[Task]], [[Script]], [[Config]] or [[Diary Record]]
|p1= entity: [[Object]], [[Control]], [[Display]], [[Group]], [[Location]], [[Task]], [[Script Handle]], [[Config]] or [[Diary Record]]


|r1= [[Boolean]]
|r1= [[Boolean]]


|x1= <sqf>if (isNull obj) then {hint "doesn't exist";};</sqf>
|x1= <sqf>
if (isNil "obj") exitWith { hint "obj variable is undefined" };
 
if (isNull obj) then
{
hint "obj variable is defined but is null";
}
else
{
hint "obj variable is defined and is not null";
};
</sqf>
 
|x2= [[Diary Record]] support before {{GVI|arma3|2.00}}:
<sqf>
private _nullRecord = objNull createDiaryRecord []; // wrong parameters = failure to create a record = null value
private _createdRecord = player createDiaryRecord ["Diary", ["title", "description"]];
if (_createdRecord isEqualTo _nullRecord) then { hint "Failed" };
</sqf>
 
[[Team Member]] support before {{GVI|arma3|2.10}}:
<sqf>private _isNull = _teamMember isEqualTo teamMemberNull;</sqf>


|seealso= [[controlNull]] [[displayNull]] [[grpNull]] [[locationNull]] [[objNull]] [[taskNull]] [[teamMemberNull]] [[scriptNull]] [[configNull]] [[typeName]]
|seealso= [[controlNull]] [[displayNull]] [[grpNull]] [[locationNull]] [[objNull]] [[taskNull]] [[teamMemberNull]] [[scriptNull]] [[configNull]] [[typeName]]
}}
}}

Latest revision as of 21:32, 19 September 2024

Logo A0.png1.00ofpe logo.png1.00Logo A1 black.png1.00Logo A2.png1.00A2 OA Logo.png1.50tkoh logo small.png1.00Arma 3 logo black.png0.50
GAGlobal
Hover & click on the images for description

Description

Description:
Checks whether the tested item is null.
Which null type the item has to be equal to depends on the type of game entity tested:
Type Object Group Control Display Location Task Script Config Diary Record Team Member
Null value objNull grpNull controlNull displayNull locationNull taskNull scriptNull configNull diaryRecordNull teamMemberNull
Since Logo A0.png1.00 Logo A1 black.png1.00 Logo A2.png1.00 Arma 3 logo black.png1.30 Arma 3 logo black.png1.54 Arma 3 logo black.png2.00 Arma 3 logo black.png2.10
⚠
A test via == does not work because a null value is not equal to anything, not even itself (configNull being the exception). See also isEqualTo.
Groups:
Variables

Syntax

Syntax:
isNull entity
Parameters:
entity: Object, Control, Display, Group, Location, Task, Script Handle, Config or Diary Record
Return Value:
Boolean

Examples

Example 1:
if (isNil "obj") exitWith { hint "obj variable is undefined" }; if (isNull obj) then { hint "obj variable is defined but is null"; } else { hint "obj variable is defined and is not null"; };
Example 2:
Diary Record support before Arma 3 logo black.png2.00:
private _nullRecord = objNull createDiaryRecord []; // wrong parameters = failure to create a record = null value private _createdRecord = player createDiaryRecord ["Diary", ["title", "description"]]; if (_createdRecord isEqualTo _nullRecord) then { hint "Failed" };
Team Member support before Arma 3 logo black.png2.10:
private _isNull = _teamMember isEqualTo teamMemberNull;

Additional Information

See also:
controlNull displayNull grpNull locationNull objNull taskNull teamMemberNull scriptNull configNull typeName

Notes

Report bugs on the Feedback Tracker and/or discuss them on the Arma Discord or on the Forums.
Only post proven facts here! Add Note
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