isNil: Difference between revisions
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{{Command|Comments= | {{Command|Comments= | ||
| arma1 |Game name= | | arma1 |Game name= | ||
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|gr1= Variables |GROUP1= | |gr1= Variables |GROUP1= | ||
| Tests whether the variable given by its name is [[nil]] or undefined, or whether the given expression evaluates to [[nil]] or [[Nothing]]. | | Tests whether the variable given by its name is [[nil]] or undefined, or whether the given expression evaluates to [[nil]] or [[Nothing]]. | ||
{{Informative | {{GVI|ofp|1.00}} This command doesn't exist in {{ofp}} but can be emulated (see '''[[#Examples|Example 5]]''').}} |Description= | {{Informative | {{GVI|ofp|1.00}} This command doesn't exist in {{ofp}} but can be emulated (see '''[[#Examples|Example 5]]''').}} |Description= | ||
| [[isNil]] variableName |Syntax= | | [[isNil]] variableName |Syntax= | ||
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|r2= [[Boolean]] - [[true]] if code returns something other than [[Nothing]] |Return value 2= | |r2= [[Boolean]] - [[true]] if code returns something other than [[Nothing]] |Return value 2= | ||
|x1= <code>[[if]] ([[isNil]] "pokus") [[then]] { pokus = 0; };</code> |Example1= | |x1= <code>[[if]] ([[isNil]] "pokus") [[then]] { pokus = 0; };</code> |Example1= | ||
| Line 51: | Line 47: | ||
[[if]] ([[format]] ["%1", foo] == _nil) [[then]] { foo = "value"; };</code> | [[if]] ([[format]] ["%1", foo] == _nil) [[then]] { foo = "value"; };</code> | ||
|Example 5= | |Example 5= | ||
| [[nil]], [[Variables]], [[Scheduler]] |See also= | | [[nil]], [[Variables]], [[Scheduler]] |See also= | ||
Revision as of 01:34, 17 January 2021
Description
- Description:
- Tests whether the variable given by its name is nil or undefined, or whether the given expression evaluates to nil or Nothing.
- Groups:
- Variables
Syntax
- Syntax:
- isNil variableName
- Parameters:
- variableName: String - name of a missionNamespace variable (e.g "someVar") or a local variable (e.g "_someVar")
- Return Value:
- Boolean - true if variable is nil
Alternative Syntax
- Syntax:
- isNil code
- Parameters:
- code: Code - code to evaluate:
- the code will be executed;
isNil { player setDamage 1; };will kill the player - the code will not be allowed to suspend while expression is evaluated, even if the parent scope allows it (see Example 4).
- the code will be executed;
- Return Value:
- Boolean - true if code returns something other than Nothing
Examples
- Example 1:
if (isNil "pokus") then { pokus = 0; };- 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:
- You can do this trick to force execute something in Unscheduled Environment.
spawn { systemChat str canSuspend; // chat shows true isNil {hint str canSuspend}; // hint shows false }; - Example 5:
- Operation Flashpoint workaround:
SQS syntax:_nil = format ["%1", _undefinedVariable] ? (format ["%1", foo] == _nil) : foo = "value"SQF syntax:_nil = format ["%1", _undefinedVariable]; if (format ["%1", foo] == _nil) then { foo = "value"; };
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