removing multiple objects from a table

General
1

I have a table called

myTable = {object1, object2, object3}

All objects from the table are from the same class, and they all have a variable called index
To I remove object2, let’s say, from the table, I would call the function removeObject(index), with a parameter of object2.index
Of course all the indecies will change after removing each object, so I call the function updateObjectIndecies() to make sure all the indecies of all the objects are accurate

function removeObject(index) --2
table.remove(myTable, index)
updateObjectIndecies()
end

function updateObjectIndecies()
for i, object in ipairs(myTable) do
object.index = i
end
end

Is there an easier way to do this? Sometimes an object doesn’t get removed from the table for some reason (in my program). Any suggestions?

2

Suggestion: usually you do not need the object to have an index pointing to its position in the table. Because the way to access objects is: for i,obj in pairs(list), or touch, or collide. So the ‘easier way to do this’ could be ‘don’t’.

3

I’m confused about what you think I should do… Do you think I should leave everything the same but not use the updateObjectIndecies() function, or something else?

4

…@edat44 Here is an example where I constantly create and destroy objects in a table. I’m showing the counts of the created and destroyed objects. I also show the count of the objects currently still in the “btab” table. A new object is created every .3 seconds and one gets destroyed when it crosses the line at y=300.


displayMode(FULLSCREEN)
supportedOrientations(PORTRAIT)

function setup()
    created=0
    destroyed=0
    et=0
    btab={}
end

-- create the object and insert it in the table
function createBall()
    c=physics.body(CIRCLE,20)   
    c.x=math.random(WIDTH)
    c.y=1000  
    c.gravityScale=math.random()
    table.insert(btab,c)
    created = created + 1
end

-- destroy the object, then remove it from the table
function destroyBall(a,b)
    b:destroy()
    b=nil
    table.remove(btab,a)
    destroyed = destroyed + 1
end

function draw()
    background(40, 40, 50)
    fill(255)
    str=string.format("Created %d        Destroyed %d       btab size %d",
        created,destroyed,#btab)
    text(str,380,200)
    stroke(255)
    strokeWidth(4)
    line(0,300,WIDTH,300)
    if ElapsedTime-et>.3 then
        createBall()
        et=ElapsedTime
    end
    noFill()
    for a,b in pairs(btab) do
        ellipse(b.x,b.y,40)
        if b.y<300 then
            destroyBall(a,b)
        end
    end
end
5

.@edat44 what do you need the index for? Where do you use it? My question is ‘do you really need it?’ and if you find out you don’t need it, well, yes, give it up, and the update too. It will be simpler. But i don’t know your program, so my suggestion might not be relevant.