isNil
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Description
- Description:
- Tests whether a variable is nil or undefined from its identifier, or whether the given expression evaluates to nil or Nothing.
- Groups:
- Variables
Syntax
- Syntax:
- isNil variableName
- Parameters:
- variableName: String - missionNamespace's or local variable's identifier (e.g "globalVariable", "_localVariable")
- Return Value:
- Boolean - true if variable is nil
Alternative Syntax
- Syntax:
- isNil code
- Parameters:
- code: Code - code to evaluate:
- Return Value:
- Boolean - true if code returns Nothing, false otherwise
Examples
- Example 1:
if (isNil "TAG_globalVariable") then { TAG_globalVariable = 0 }; if (isNil "_localVariable") then { hint "_localVariable is nil" };
- Example 2:
isNil { player getVariable "someVar" };
- Example 3:
_myArray = [0, 1]; isNil { _myArray select 0 }; // returns false isNil { _myArray select 1 }; // returns false isNil { _myArray select 2 }; // returns true isNil { _myArray select 3 }; // throws a script error. only length+1 select is allowed
- Example 4:
- This trick forces executing something in Unscheduled Environment:
0 spawn { systemChat str canSuspend; // chat shows true isNil { hint str canSuspend }; // hint shows false };
- Example 5:
- Operation Flashpoint String comparison workaround:
; SQS Syntax _nil = format ["%1", _undefinedVariable] ? (format ["%1", variableToTest] == _nil) : hint "variableToTest is nil"
// SQF Syntax _nil = format ["%1", _undefinedVariable]; if (format ["%1", variableToTest] == _nil) then { hint "variableToTest is nil" };
Additional Information
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
Categories:
- Scripting Commands
- Introduced with Armed Assault version 1.00
- ArmA: Armed Assault: New Scripting Commands
- ArmA: Armed Assault: Scripting Commands
- Arma 2: Scripting Commands
- Arma 2: Operation Arrowhead: Scripting Commands
- Take On Helicopters: Scripting Commands
- Arma 3: Scripting Commands
- Command Group: Variables