Check if a variable exists [Solved]

[Brandon Gale]

Hey, can someone help me to check if a variable exists?

Here is my code:

if !variable_instance_exists(enemy[i], enemy_pos_x) enemy_pos_x = 0;

I have a loop that loops through all instances of objects in a room and I'm trying to make sure they all have this variable (even if it is not being used) so that I don't hit an error.

Somehow the code is not doing its job and objects are still hitting an error when they have not been previously assigned the variable.

Any ideas why? Let me know if more of my code is needed here.

 

[FrostyCat]

Arguments:
instance_id The unique ID value of the instance to check
name The name of the variable to check for (as a string)

enemy_pos_x isn't a string. "enemy_pos_x" is a string.

 

[Brandon Gale]

enemy_pos_x isn't a string. "enemy_pos_x" is a string.

Ha! Of course it is a silly syntax error. I'm coming from programming in VBA, so the syntax adjustment is a work in progress.

I will give this a go! Thanks!

I am getting this:

FATAL ERROR in
action number 1
of  Step Event0
for object obj_player:

Variable obj_Moon.enemy_pos_x(100018, -2147483648) not set before reading it.
 at gml_Object_obj_player_Step_0 (line 14) -        enemy.enemy_pos_x += (room_width/2);
############################################################################################
--------------------------------------------------------------------------------------------
stack frame is
gml_Object_obj_player_Step_0 (line 14)

I guess I am having problems with variable scope. It has been an area of difficulty for me.

 

[Brandon Gale]

I think I fixed it.

if !variable_instance_exists(enemy[i], enemy_pos_x) enemy_pos_x = 0;

Changed to this:

if !variable_instance_exists(enemy[i], "enemy_pos_x") enemy[i].enemy_pos_x = 0;

Using your fix and also putting the instance id in front of the variable. Thanks so much!