how can i parse a display group?

screengroup = display.newGroup()

local function square_invisible_up(img_name)

    

    local rect = {}

    local pos = 1

    for i = 1, #img_name do

        rect[i] = display.newRoundedRect( screenGroup, (halfW/2 + 100) + (pos * 120), (halfH/2) * 1.5, 100, 100, 3)

        rect[i]:setFillColor(0, 0, 0, 0)

        rect[i]:setStrokeColor(1, 1, 1)

        rect[i].strokeWidth = 5

        screenGroup.name = i

        pos = pos + 1

    end

end

for k,v in pairs(screenGroup) do – i don’t know how it works a display group  

        print(screenGroup[k].name)

   end

in lua i can parse a table but with a display group i can’t , is it possible to do the same with a display group?

http://docs.coronalabs.com/api/type/GroupObject/numChildren.html

http://docs.coronalabs.com/api/type/GroupObject/numChildren.html