Need Little help ^^

[Neolitik]

hello any !

i'm trying to understand Lua , love and all the rest ...( female , world war ... )

I have write this :

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--AutoGenerated by DEVotion
PhyRect={}
PhyRect.Rect={}
function Add(Tx,Ty)
	local R={}
	R.Body= love.physics.newBody(PhyWorld, Tx*32, Ty*32,0)
	R.Shape=love.physics.newRectangleShape(R.Body,32,32)
	R.Shape:setRestitution(0.5)
	print( table.getn(PhyRect.Rect))
	table.insert(PhyRect.Rect,R)
	--return Rect
end

function RemoveAll()
	for k,v in ipairs(PhyRect.Rect) do
	     v.Shape:destroy()
	     v.Body:destroy()
	     table.remove(PhyRect.Rect,k)
	     print("remove ="..k.."  tgn"..table.getn(PhyRect.Rect).."")
	end
end

But My RemoveAll() function dont remove all !

Why my function don't remove all ?

If i 'm add :
while table.getn(PhyRect.Rect) > 0 do .......end

in the function , it's ok

thank for help !

[Robin]

Let me help you visualize what happens if you do it the first way:
Frame one:

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{ --this is all pseudocode
> Rect1,
  Rect2,
  Rect3,
  Rect4,
}

(The little arrow is the pointer of the for loop)
The first rect gets deleted, and the loop pointer advances one position:

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{
  Rect2,
> Rect3,
  Rect4,
}

The third rect gets deleted, and the loop pointer advances one position:

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{
  Rect2,
  Rect4,
>
}

Lua thinks now: "Oh, apparently, the loop has ended. That means I'm all done."
Thus the loop terminates, leaving half the entries as they are.

I may be mistaken about the precise process and results, but you get the gist of it?

[Neolitik]

Hum i m think i have dont understand Pairs and Ipairs in lua.

Pairs : for 2 ..4 ..6 ... ?
Ipairs : for 1..3..5..7..?

hum, i dont understand the help of lua !

how make a "For Block " for pass all entry of my array ?

[Robin]

It does visit every entry of your table! The problem is that you remove entries while visiting. A solution would be:

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for i=#myTable,1,-1 do
  table.remove(myTable, i)
end

The difference between pairs and ipairs is visible if you use them on a table like:

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t = {35, 6, 20, [42] = 4, name = "James"}

Try

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for k, v in pairs(t) do
  print(k, v)
end

and

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for k, v in ipairs(t) do
  print(k, v)
end

, and you can see the difference yourself.

(hint: pairs visits every key, ipairs visits only numeric keys, beginning at 1 and stopping when the value is nil.

[bartbes]

ill try to explain pairs and ipairs:

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t = {2,9}
t[4] = 5
print("ipairs")
for i,v in ipairs(t) do
--loops through numerical indices till empty
print(i,v)
end
print("pairs")
for i,v in pairs(t) do
--loops through all indices no order
print(i,v)
end
--[[prints
ipairs
1 2
2 9
pairs
1 2
2 9
4 5

[Neolitik]

Thank , i have try your code in the Lua demo live.
I 'm understand more now

Big thank for all !