Group Display Objects vs. Tables in Corona Lua - lua

Question

First time post and I sincerely apologize if this has been answered in any other post but I have not been able to find a resolution for the problem I'm facing on this or any other site. I'm a new programmer self-teaching with web tutorials and any other resource I have found. I am trying to create code which will spawn characters and allow you to call them. I've had trouble assigning an index value to the individual instances I have created with a for function. I have tried to establish the instance as both a table and a group display object. If anyone is able to point me in the direction of any resources to get a more indepth understanding of tables and group display objects for the Corona SDK implementation of Lua I'm sure that my problem is that I don't have a thorough enough understanding of these particular functionalities and how they work. Here is the code I've written so far.
-- Character Game
require "sprite"
require "ui"
local background = display.newImage("Background Placeholder.png")
halfW = display.viewableContentWidth / 2
halfH = display.viewableContentHeight / 2
local numCharacters = 20
local roundedRect = display.newRoundedRect( 365, 20, 110, 40, 8 )
roundedRect:setFillColor( 0, 255, 0, 80 )
score = 0
t = ui.newLabel{ bounds = { 370, 30, 100, 40 },
text = "Score " .. score,
textColor = { 255, 0, 20, 255 },
size = 18,
align = "center"
}
local scoreboard = function ( event )
t:setText( "Score " .. score )
end
Runtime:addEventListener( "enterFrame", scoreboard )
local group = display.newGroup()
local character = sprite.newSpriteSheetFromData( "Character Placeholder.png", require("Character Placeholder").getSpriteSheetData() )
local characterSet1 = sprite.newSpriteSet(character,1,8)
sprite.add(characterSet1,"character",1,8,1500,0)
local characterplay = function( event )
score = score + group.points
group[i]:removeSelf()
end
do
for i=1, numCharacters do
group:insert(sprite.newSprite(characterSet1))
group[i].xScale = .2
group[i].yScale = .2
group.points = 50
group[i]:setReferencePoint ( display.BottomCenterReferencePoint )
group[i]:translate( halfW + math.random( -100, 100 ), halfH + math.random( -130, -110 ) )
end
timer.performWithDelay( 500, charactermovie )
for i=1, 21 do
timer.performWithDelay( math.random( 500, 5000 ) , charactermove )
charactermove = function(event )
transition.to( group[i], { time=10000, y = 580 } )
transition.to( group[i], { time=8000, x = math.random( 0, 480 ) } )
transition.to( group[i], { time=7000, xScale = 1.5} )
transition.to( group[i], { time=7000, yScale = 1.5} )
group[i]:prepare("character")
group[i]:play()
end
group[i]:addEventListener( "tap", characterplay )
end
end
charactermovie = function( event )
group[i]:prepare("character")
group[i]:play()
end
local function spriteListener( event )
print( "Sprite event: ", event.sprite, event.sprite.sequence, event.phase )
end
for i, group in pairs(group) do print (group, i, v) end
I'm currently getting an "attempt to index field '?' at the line containing this code "group[i]:addEventListener( "tap", zombieplay )" upon launch and a "nil key supplied for property lookup" error at the "group[i]:removeSelf()" line of the "zombieplay" function. I've tried moving the offending code to a variety of locations to see if this is a scoping issue but I largely run into the same error and believe I may not properly understand indexes and keys... I've found that the app functions as intended but I have to call index keys 1 through 21 to get them all to move even though I am only calling for 20 characters and the removeSelf line throwing errors is not removing the individual characters. I'm going to try writing a module for the characters and see if that helps clear any of this up. I will post my results shortly.

Answer 1

Your characterplay and charactermovie functions are trying to use the variable i, this is outside the functions scope.
There is a property of event called target, which is used to get the event callee. You want to do something like this:
local characterplay = function( event )
score = score + group.points
event.target:removeSelf()
end