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How can modify a single number in array ?

Example :
I have a arraw with [3 ,1] and i want to modify only the first value to 6
Like this = [6 ,1]

I don't think there is an easy method for this. I just feed in the same variables from before.

Code: Select all

someArr = [3, 1]
someArr = [6, someArr(1)]


Use the index.

Array=[3, 1]
3 : index (0)
1 : index (1)

So, use something like Array(0)=6
Now Array=[6, 1]

No one worked here

i want to make a subtraction in one array element

When do you want it to be modified ?
What's the action that provocs the substraction ?

Can you tell more ?

I want to make a subtraction in the anglevel element0 oncollide(){}

Write a value to a single array element.

Currently you cannot write to a single array element in the usual way that you would do it in many other programming languages. For example, you cannot do: scene.my.array(17)=2.035. So, back around 2012, one of the clever Algodoo users wrote a function that allows writing to a single array element. Here is the function code that you must first enter into the console:

//copy starts here//
scene.my.xFor := (n1, n2, code) => {
n2 > n1 ? {
m := (n1 + n2) / 2;
scene.my.xFor(n1, m, code);
scene.my.xFor(m + 1, n2, code)
} : {code(n1)}
};

scene.my.WriteArray := (array, n, new) => { result := []; scene.my.xFor(0, string.length(array)-1, (i)=>{ i == n ? { result = result ++ [new]} : {result = result ++ [array(i)]} }) }
//copy ends here//

Then in your geometry script, you call the function like this:

array=scene.my.writearray(array,n,value) where, "array" is the name of the array that you want to write to. "n" is the element number (0 is the first element). And "value" is the value that you want to write to the element. For example:

scene.my.colorarray=scene.my.writearray(scene.my.colorarray,17,3.1416)


NOTE: scene.my.xfor is a FOR loop that user Kilinich designed. The following is an example of useage:
scene.my.xFor(0,10000, (n) => {print(n)})

In order to write to an array element, you first must enter the above two functions (just copy and paste ONCE) into the Algodoo console and hit Return. Then, in a geometry, you use the scene.my.writearray function like this:

scene.my.ArrayName = scene.my.writearray(scene.my.ArrayName, array element number, new data)

Note: the "element number" can be a calculated value, or it can be a variable containing the element number.

I have been using this work-around since 2012 when I learned it. It's GREAT!

Too much ting to do one thing

One technique I tend to use in bigger equations is this:

Array1 = [3,1];

Array2 = Array1*[0,1]+[6,0]

Array2 is now [6,1]

However, as already mentioned, the easiest way for such small things is simply:

Array1 = [6,Array1(1)]

You can also do it with this:

Scene.my.setarr = (arr, n, value)=>{ arr(0..n-1) ++ [value] ++ arr(n+1..string.length(arr)-1) };

and to use it just:

array = [1,2,3,4,5];
array = Scene.my.setarr(array, 3, 100);
array; //should now contain [1,2,3,100,5]

This may not be terribly fast, but it sure is flexible! (Although it is definitely an overkill for something this simple)

Thanks, Kutis 96! I'll play around with your method, and if it works better than the method that I have been using, then I just might adopt it.