local myTable = {
    ["key1"] = 1,
    ["key2"] = 2,
    ["key3"] = 3,
}
 
for k, v in pairs(myTable) do
        print(myTable[k])
end

local myTable = {
    ["key1"] = 1,
    ["key2"] = 2,
    ["key3"] = 3,
}
 
 
local function __genOrderedIndex( t )
    local orderedIndex = {}
    for key in pairs(t) do
        table.insert( orderedIndex, key )
    end
    table.sort( orderedIndex )
    return orderedIndex
end
 
local function orderedNext(t, state)
    -- Equivalent of the next function, but returns the keys in the alphabetic
    -- order. We use a temporary ordered key table that is stored in the
    -- table being iterated.
 
    --print("orderedNext: state = "..tostring(state) )
    if state == nil then
        -- the first time, generate the index
        t.__orderedIndex = __genOrderedIndex( t )
        key = t.__orderedIndex[1]
        return key, t[key]
    end
    -- fetch the next value
    key = nil
    for i = 1,table.getn(t.__orderedIndex) do
        if t.__orderedIndex[i] == state then
            key = t.__orderedIndex[i+1]
        end
    end
 
    if key then
        return key, t[key]
    end
 
    -- no more value to return, cleanup
    t.__orderedIndex = nil
    return
end
 
--This is the function you will use to replace "pairs"
local function orderedPairs(t)
    -- Equivalent of the pairs() function on tables. Allows to iterate
    -- in order
    return orderedNext, t, nil
end
 
 
for k, v in orderedPairs(myTable) do
        print(myTable[k])
end

local function shuffle(t)
    local rand = math.random 
    assert(t, "table.shuffle() expected a table, got nil")
    local iterations = #t
    local j
    
    for i = iterations, 2, -1 do
        j = rand(i)
        t[i], t[j] = t[j], t[i]
    end
end
 
--Usage
shuffle(myTable)

local function doesFileExist(theFile, path)
        local thePath = path or system.DocumentsDirectory
        local filePath = system.pathForFile(theFile, thePath)
        local results = false
                
        local file = io.open(filePath, "r")
            
        --If the file exists, return true
        if file then
                io.close(file)
            results = true
        end
         
        return results
end
 
--Usage
doesFileExist("levels.data") --Returns true/false
 
--Or
doesFileExist("levels.data", system.ResourceDirectory) --Returns true/false

local function getDistanceBetween(obj1, obj2)
        return math.ceil(math.sqrt( ((obj2.y - obj1.y) * (obj2.y - obj1.y)) + ((obj2.x - obj1.x) * (obj2.x - obj1.x)) ))
end
 
--Usage
 
local plane = display.newRect(100, 100, 40, 40)
local bird = display.newRect(200, 100, 40, 40)
 
getDistanceBetween(plane, bird) --In this case it will return 100

local function printMemUsage()          
        local memUsed = (collectGarbage("count")) / 1000
        local texUsed = system.getInfo( "textureMemoryUsed" ) / 1000000
        
        print("\n---------MEMORY USAGE INFORMATION---------")
    print("System Memory Used:", string.format("%.03f", memUsed), "Mb")
        print("Texture Memory Used:", string.format("%.03f", texUsed), "Mb")
    print("------------------------------------------\n")
     
    return true
end
 
--Usage
 
printMemUsage() --Best to call when you are finished changing scenes once