Test <null> ?

[alleycat 28]

How to test if a variable is <null>?

I want to display a variable that might not exist for certain units. It reports <null> when displaying.

[Valfunction 1]

I don't really understand what you are trying to do but to test if a variable is null:

if (_variable == null) then     //alternatively if (_variable == 0) then
      {
           //magic
      }

[Rydygier 1309]

Use:

isNull

eg:

if not (isNull _var) then {hint format ["%1 is not null",_var]};

[alleycat 28]

Use:

isNull

eg:

if not (isNull _var) then {hint format ["%1 is not null",_var]};

if not (isNull _aff) then {hint format ["%1 is not null",_aff]};
if  (isNull _aff) then {hint format ["%1 is  null",_aff]};

Code before and after this does run.

This never triggers.

Perhaps I explained what I want to do wrong:

I want to display a variable that might exist. If it does not exist (was not defined for the unit) then it returns literally <null>. I would like to test that.

[cuel 25]

I think you're looking for isNil.

if (isNil "_aff") then {

};

[galzohar 31]

Undefined variable - Check with isNil "varName". Variable defined but points at no object - Check with isNull varName. Noticee the difference in quotes.

call compile "blah"; //Undefined variable error
if (isNil "blah") then {hint "Blah is nil"} else {hint "Blah is not nil"}; // blah is nil here as it is undefined
if (blah) then
{
// This code will never be executed as blah is an undefined variable. No error is given.
}
else
{
// This code will never be executed as blah is an undefined variable. No error is given. Yes, both the "then" and the "else" get ignored.
}
blah = "Jeep" createVehicle (position player);
if (isNull "blah") then {diag_log "blah is null"} else {diag_log "blah is not null"}; // will log "blah is not null" as it points at a valid vehicle.
deleteVehicle blah;
if (isNull "blah") then {diag_log "blah is null"} else {diag_log "blah is not null"}; // will log "blah is null" as the vehicle have been deleted.
if (isNil "blah") then {hint "Blah is nil"} else {hint "Blah is not nil"}; // blah is not nil here as it is undefined, it simply doesn't point at any valid object