Array cell access [help needed].

[savask]

As I know, Phun don't allow you to change one cell of the array, so I tried to make a special function:

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scene.my.addr = 0;         scene.my.maxr < scene.my.a ? {scene.my.maxr = scene.my.a} : {};         scene.my.copy = scene.my.ram;         scene.my.ram = [0];         for(scene.my.a - 1, (addr)=>{scene.my.ram = scene.my.ram ++ scene.my.copy(addr)});         scene.my.ram = scene.my.ram ++ scene.my.b;         scene.my.addr = scene.my.a + 1;         for(scene.my.maxr, (addr)=>{scene.my.ram = scene.my.ram ++ scene.my.copy(addr)});         scene.my.com = scene.my.com + 1

Scene.my.a - adress, scene.my.b - new value,scene.my.ram - array, scene.my.copy - copy array.
But it don't work
There is "List index out of bounds" error.

[KarateBrot]

Can you please show us your scene.my.copy function?

[savask]

It isn't function, it is array.

[KarateBrot]

Ok, I know the reason. The value of scene.my.a - 1 or scene.my.maxr is too big.

Let's make an example:

I have an array like this:
scene.my.array = [0,1,2,3,4]

Now I want to call a value of the array. For example the third:
scene.my.array(2)

The answer will be of course 2.
But you have to watch out. What if you call the 6th or 7th... value? (Remember: we have got 5 values in our array)
scene.my.array(5)

An error code appears that says "List index out of bounds" because you call a value in the array that doesn't exist. In other words the list index (that's 5 here) exceeds the number of values in your array.

[savask]

No, arrays starts at 0.
scene.my.array(3) = 3

[KarateBrot]

No, arrays starts at 0.
scene.my.array(3) = 3

Oh, yeah of course, thanks. A small mistake but I already corrected it. I have chosen [0,1,2,3,4], starting at 0 to make it more easy so that the list index is the same as the value but all the same I made this silly mistake

[savask]

I tried to use small address value, and big number of cells, but it don't work too.

[KarateBrot]

did you try it with both of your for-functions?

[savask]

Can't understand exactly what do you mean, but if you about scene.my.copy, so yes, I did.

[KarateBrot]

for(scene.my.a - 1, (addr)=>{scene.my.ram = scene.my.ram ++ scene.my.copy(addr)});
for(scene.my.maxr, (addr)=>{scene.my.ram = scene.my.ram ++ scene.my.copy(addr)});

It seems like "scene.my.a - 1" or "scene.my.maxr" is too big. You have to keep these variables as low as the number of cells in your scene.my.copy array.

[savask]

I tried, and it don't work again!
Scene.my.maxr - it is the biggest address used.

[KarateBrot]

Are you sure you did everything correct?

in the console type "scene.my.maxr = 2", "scene.my.a = 2" and "scene.my.ram = [3,5,6,6,4]"

Now test it again.

[savask]

No, this don't too...

[KarateBrot]

I don't know what you're doing but I tested your code, too... and it works
After I corrected the "List index out of bounds" error a new error occured that said "++ only add lists" but you can correct this by making [] brackets around "scene.my.copy(addr)". it looks like this:

for(scene.my.a - 1, (addr)=>{scene.my.ram = scene.my.ram ++ [scene.my.copy(addr)]});
for(scene.my.maxr, (addr)=>{scene.my.ram = scene.my.ram ++ [scene.my.copy(addr)]});

But to adjust the values of the variables definitely solves your out of bound error problem.

[savask]

It work with the brackets, thanks!

[KarateBrot]

oh okay so you didn't read the error message that was the problem

[savask]

There are warning messages, but I have found one bug in my algorithm.

[KarateBrot]

If something is wrong ask again I gladly like to help

[savask]

Are there a limit of number of array cells?

[KarateBrot]

I don't know but I just tested it with about 4500 cells and it's still working so if there's a limit at 4920587248974 cells it shouldn't bother you

[savask]

Strange...
I can't use more then 50 cells.

[KarateBrot]

very strange. what's the error message?

[immibis]

For loops can only repeat up to 40 times because they're implemented recursively.
In C:\Program Files\Algodoo\thyme.cfg:

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for = (n, what)=>{
    n <= 0 ? false : {
        for(n - 1, what);
        what(n-1)
    }
};


You can only call functions up to 40 levels deep, so this fails for anything higher.

I made a better for loop at http://www.algodoo.com/forum/viewtopic.php?f=13&t=371&p=8695#p8695, but any loop (including this) will be very slow for large numbers of iterations.

[KarateBrot]

The problem was a different one. It wasn't the loop limit of the for-function, it was an array error. But it's a cool idea to mention it if savask needs deeper for functions and gets the overflow error, too.
Gradyfitz also made an extended loop function here at Tutorial 20. It seems like it's faster but "only" handles up to 490 loops. If you need more than 490 loops yours is very cool because I couldn't find a limit even with about 5000 loops.

[savask]

Yes, immibis was right. This is cause of for-loop limit.
Can you show me some examples of using your for-function?