What is the problem here? This code is supposed to remove texts after I shoot it and at the same time increasing the score. Also, can someone explain what does the other.name actually mean? I don't quite fully understand it..(And yes its the first if statement that has the error)
function wordCollision(e)
if (e.other.name == 'balloonText') then -- error here: attempt to index field 'other'(a nil value)
display.remove(e.other)
e.other = nil
score.text = score.text + 50
score.anchorX = 0
score.anchorY = 0
score.x = 200
score.y = 50
target.text = target.text - 1
else
if (e.other.name == 'balloonTextt') then
display.remove(e.other)
e.other = nil
score.text = score.text + 50
score.anchorX = 0
score.anchorY = 0
score.x = 200
score.y = 50
target.text = target.text - 1
end
end
end
It simply means that there is no entry with key 'other' in the table e.
If if you want to look up something in e.other you'll have to assign a table to that key:
e.other = {}
Using metatables, you could make it go automatically:
mt = {}
mt.__index=function(t,k) if ~rawget(t,k) then t[k]=setmetatable({},mt) end return t[k] end
e={}
e=setmetatable(e,mt)
e.other.name='foo'
Watch out with this though, because any lookup to a non-existant field will create a new table for it, which may or may not be what you want (aside of the fact that this overwrites any existing metatable on e):
for k,v in pairs(e) do print(k,v) end
print(e.bar)
for k,v in pairs(e) do print(k,v) end
Problem could be that you have the e.other = nil in there, but don't reset e.other to something after, so when the wordCollision() gets called again, it is e.other is nil. Could also be that e.other is never initialized in the first place. Verify it is initialized somewhere before wordCollision() is ever called, and verify that it is re-set to something between two calls to wordCollision().
Related
I'm trying to shuffle a table's contents randomly. It works fine, except sometimes it doesn't return all the contents of the table. I printed out some of the keys of the table before shuffling, and they returned nil, but I'm not sure how to fix that. Here's the Lua:
local tab = {1,2,3,4,5,6,7,8,9,10}
function ReturnRandomTable(t)
local newt = {}
local i = 1
repeat
local rand = math.random(1,#t)
newt[i] = t[rand]
print(t[rand]) --sometimes prints nil
t[rand] = nil
i = i + 1
until #t == 0
return newt
end
table.shuffle = function(t)
local newt = ReturnRandomTable(t)
for i = #t,1,-1 do
t[i] = nil
end
return newt
end
local randt = table.shuffle(tab)
for _,v in pairs(randt) do
print(v)
end
Any help would be appreciated!
Solved by changing t[rand] = nil to table.remove(t,rand).
I'm trouble to understand self and local value.
Here is my asteroid.lua. I created local asteroid inside :create and was trying to use it other function but it is not working correctly.
-- Class Declaration
Asteroid = {}
Asteroid.__index = Asteroid
function Asteroid:create()
local asteroid = {}
setmetatable(asteroid, Asteroid)
-- Animation Data
asteroid.frames = {}
asteroid.currentFrame = 1
asteroid.frameDuration = 0.04 -- 0.016
asteroid.frameTimeRemaining = asteroid.frameDuration
asteroid.x = 0
asteroid.y = 0
return asteroid
end
function Asteroid:init()
-- Use a loop to load a bunch of files!
for index= 0, 15 do
-- Use logic to build the filename...
file = 'art/large/a100'
-- Take into account the extra 0
if index < 10 then
file = file .. '0'
end
-- Add the file number and then .png
file = file .. tostring(index) .. '.png'
-- Load the file... (we'll use lua's 1 index to be kind)
self.frames[index + 1] = love.graphics.newImage(file)
if self.frames[index + 1] ~= nil then
print('Loaded frame ' .. tostring(index + 1))
end
end
-- Set the velocity randomly!
self.velocity = {}
self.velocity.x = math.random(-76.0, 76.0)
self.velocity.y = math.random(-76.0, 76.0)
end
Asteroid.updateAnimation = function(deltaTime)
-- Catch variable into 'easy-to-type' one
local ftr = Asteroid.frameTimeRemaining
THIS PART(local ftr) IS MY PROBLEM: ATTEMPT TO INDEX A NIL VALUE.
I tried different ways like self.frameTimeRemaing but I couldn't figure out.
Is anyone know how I can fix this local?
-- Subtract time
ftr = ftr - deltaTime
-- If the frame is over...
if ftr < 0 then
Asteroid.nextFrame()
Asteroid.frameTimeRemaining = Asteroid.frameDuration
else
Asteroid.frameTimeRemaining = ftr
end
end
Without seeing the rest of the code, I can only guess. Try this:
function Asteroid:updateAnimation(deltaTime)
-- use self instead of Asteroid in this function
end
I'm trying to implement a speed-based turn system for a roguelike. I've set up a Mob class using metamethods, so that assigning the following to a variable will spawn a mob into the map at certain grid coordinates:
function Mob:spawn(x,y,m)
local mob = {}
setmetatable(mob, Mob)
mob.x = x
mob.y = y
mob.is_monster = m
return mob
end
Once that's done, I call the following:
function Mob:roll_call()
who_is_here[self.y][self.x] = self.is_monster
self.turn_counter = self.turn_counter * math.random(0.9, 1.1)
table.insert(allTurnCounters, self.turn_counter)
end
This puts the mob's self.turn_counter into a table. Meanwhile, in another module, I've defined these two functions, the heart of the problem:
function turn.decrement_counters(dt) -- runs in Dungeon.update(dt) and subtracts from allTurnCounters
for i = 1,#allMobsSpawned do
if allTurnCounters[i] <= 0 then
allTurnCounters[i] = 0
turn_active = true
whose_turn = i
return
elseif allTurnCounters[i] > 0 then
allTurnCounters[i] = allTurnCounters[i] - (10 * dt)
end
end
end
function turn.whose_is_it() -- called when an entry in allTurnCounters goes zero
if whose_turn == 1 then -- spots 1 and 2 in the spawn list are only ever for players
player1.my_turn = true -- turns on player 1's keys
elseif whose_turn == 2 then
player2.my_turn = true -- turns on player 2's keys
elseif whose_turn >= 3 then -- above 3 we're in monster territory
end
end
I've decided that the first two instances of Mob to be initialized will always be players 1 and 2, assigned to the variables player1 and player2, respectively. And, as it is, it works fine for passing control back and forth between players! But obviously, that's not enough for a fully-featured game. I need monsters, too.
The allTurnCounters table gets new entries, in order, from every mob that spawns (a class which includes both the players and the monsters, so they can share stats). Here's my question: How can I get Lua to dynamically retrieve the name of the table associated with a given turn_counter/value within that table, and use it to take turn priority, even in the event that I don't know what's been procedurally spawned ahead of time or what place it will occupy in the spawn order?
I have 3 ideas, none of which I'm solid on how to implement. One method would be something like sending the entire instance table to another table, rather than just their turn_counters, and then somehow grabbing a pair of values (the table itself and my_turn within the table), updating my_turn's value directly.
Another method might be to use the environment _G... somehow. I'm still poring over Chapter 14 of PiL trying to adapt it to my purposes, but value = _G[varname] seems to be a powerful bit of code I might be able to use for this. Not sure how, just yet.
My last idea was to maybe write some kind of string-sensing find-replace that can grab some other value in each mob's table and then pop it on the front of my_turn. Like, assigning some value with a known pattern for each mob type, that I can use in a string.find and then a string.gsub, to like... manually make the code line read as intended. Seems inelegant, though.
I had good luck with asking my previous Lua/Love2D question here, so I figured let's toss it out there while I'm thinking!
Here is my suggestion for how you should implement this:
Instead of allTurnCounters[i], give mobs a turn_counter property and use allMobsSpawned[i].turn_counter. Then, delete allTurnCounters.
Instead of storing the mob number in whose_turn, store the mob itself. (Note: when I say "the mob itself", it's short for "a reference to the mob itself")
So instead of
whose_turn = i
you would have:
whose_turn = allMobsSpawned[i]
Now whose_turn holds the mob whose turn it is. You can easily check whose_turn == player1, whose_turn == player2, etc. As a bonus, it doesn't rely on the players being the first mobs any more.
You can access the mob's properties through whose_turn - if whose_turn == player1 is true for example then whose_turn.x accesses the same field as player1.x
Here's a somewhat janky solution that can be made more elegant by incorporating the method from the other answer. This is what I came up with on my own while waiting for an answer.
-- in "Mob.lua" module
function Mob:roll_call()
who_is_here[self.y][self.x] = self.is_monster
self.turn_counter = self.turn_counter * math.random(0.9, 1.1)
table.insert(allMobs, {self.name, self.turn_counter})
if self.is_monster == true then
table.insert(allMonsters, {self.name, self.turn_counter})
end
end
function Mob:move(dx, dy)
who_is_here[self.y][self.x] = nil
self.x, self.y = self.x + dx, self.y + dy
who_is_here[self.y][self.x] = self.is_monster
self.turn_counter = 1 * self.speed
for k,v in ipairs(allMobs) do
if v[1] == self.name then
v[2] = self.turn_counter
end
end
self.my_turn = false -- flags turn is over
turn_active = false -- flags no active turn
end
-- in "turn.lua" module
function turn.decrement_counters(dt)
if turn_active == false then
for k,v in ipairs(allMobs) do
v[2] = v[2] - (10 * dt)
if v[2] < 0 then
v[2] = 0
turn_active = true
whose_turn = v[1]
return
end
end
else turn.whose_is_it()
end
end
function turn.whose_is_it()
if whose_turn == player1.name then
player1.my_turn = true
elseif whose_turn == player2.name then
player2.my_turn = true
elseif whose_turn == ant1.name then
ant1.my_turn = true
end
end
turn.whose_is_it() is the part that will need refining. If I use immibis' method of assigning allMobs[i].turn_counter, that will simplify things considerably and allow for future expansion. This answer only works for player1, player2, and an ant called ant1 in particular.
I was on stack a few days back for help inserting records to prevent duplicates. However the process to enter these is slow and they slip in.
I have a user base of about 10,000 players, and they have duplicate entries.. I've been trying to filter out these duplicates without success. The examples on stack have no panned out for me.
Here is a clip from my table
[18] =
{
["soldAmount"] = 25,
["buyer"] = [[#playername]],
["timestampz"] = 1398004426,
["secsSinceEvent"] = 55051,
["guildName"] = [[TradingGuild]],
["eventType"] = 15,
["seller"] = [[#myname]],
},
[19] =
{
["soldAmount"] = 25,
["buyer"] = [[#playername]],
["timestampz"] = 1398004426,
["secsSinceEvent"] = 55051,
["guildName"] = [[TradingGuild]],
["eventType"] = 15,
["seller"] = [[#myname]],
},
The timestamp's match and they should not have been added.
for k,v in pairs(sellHistory) do mSavedTHVars.Forever_Sales[k] = v
if mSavedTHVars.Forever_Sales.timestampz ~= sellHistory.timestampz then
table.insert(mSavedTHVars.Forever_Sales, sellHistory)
end end
Now, I need to find out how to remove the current duplicates, and here is what I've tried.
function table_unique(tt)
local newtable = {}
for ii,xx in ipairs(tt) do
if table_count(newtable.timestampz, xx) ~= tt.timestampz then
newtable[#newtable+1] = xx
end
end
return newtable
end
I hope this information provided was clean and understandable.
Thanks!
UPDATE
Attempt #20 ;)
for k,v in pairs(mSavedTHVars.Forever_Sales) do
if v == mSavedTHVars.Forever_Sales.timestampz then
table.remove(mSavedTHVars.Forever_Sales,k)
end
end
No luck yet.
UPDATE
This has worked
for k,v in pairs(mSavedTHVars.Forever_Sales) do mSavedTHVars.Forever_Sales[k] = v
if v.timestampz == mSavedTHVars.Forever_Sales.timestampz then
table.remove(mSavedTHVars.Forever_Sales, k)
end
end
IS this a good approach?
Assuming that mSavedTHVars.Forever_Sales[18] and mSavedTHVars.Forever_Sales[19] are the tables you listed in your post, then to remove all duplicates based on same time stamp it is easiest to create a "set" based on timestamp (since the timestamp is your condition for uniqueness). Loop through your mSavedTHVars.Forever_Sales and for each item, add item to new table only if its timestamp not already in set:
function removeDuplicates(tbl)
local timestamps = {}
local newTable = {}
for index, record in ipairs(tbl) do
if timestamps[record.timestampz] == nil then
timestamps[record.timestampz] = 1
table.insert(newTable, record)
end
end
return newTable
end
mSavedTHVars.Forever_Sales = removeDuplicates(mSavedTHVars.Forever_Sales)
Update based on Question Update:
My comment on following proposed solution:
for k,v in pairs(mSavedTHVars.Forever_Sales) do
mSavedTHVars.Forever_Sales[k] = v
if v.timestampz == mSavedTHVars.Forever_Sales.timestampz then
table.remove(mSavedTHVars.Forever_Sales, k)
end
end
The problem is that I don't see how that can work. When you do for k,v in pairs(mSavedTHVars.Forever_Sales) do then v is mSavedTHVars.Forever_Sales[k] so the next line mSavedTHVars.Forever_Sales[k] = v does nothing. Then if v.timestampz == mSavedTHVars.Forever_Sales.timestampz compares the timestamp of v, i.e. of mSavedTHVars.Forever_Sales[k], with value of a timestampz field in mSavedTHVars.Forever_Sales. But latter is a table without such field, so right-hand-side of == will be nil, so the condition will only be true if v.timestampz is nil, which I don't think is ever the case.
The main reason that I used a solution of creating new table instead of removing duplicates from the existing table is that you can edit a table while iterating over it with pairs or ipairs. If you were to use a reverse counter, it would probably be ok (but I have not tested, test to be sure):
function removeDuplicates(tbl)
local timestamps = {}
local numItems = #tbl
for index=numItems, 1, -1, do
local record = tbl[index]
if timestamps[record.timestampz] ~= nil then
table.remove(newTable, index)
end
timestamps[record.timestampz] = 1
end
end
Also I think the intent of the function is not as clear, but maybe this is just personal preference.
I am making a shooter game using the corona sdk...
My problem is that i am trying to delete an object(that is part of an array)when it leaves the screen.. when i do, i get an error that says 'trying to compare nil value to variable' which refers to a simple move function for every object in the array. Here is relevant parts of code:
function addAlien()
listeners('add')
end
function listeners(action)
if(action == 'add') then
Runtime:addEventListener('enterFrame',update)
enemyTimer = timer.performWithDelay(800,addEnemy,0)
else
Runtime:removeEventListener('enterFrame',update)
timer.cancel(enemyTimer)
end
end
function addEnemy(e)
enemy = display.newImage('drone.png')
enemy.x = 500
enemy.y = math.floor(math.random()*300)
enemy:scale(-0.1,0.1)
enemy.speed = math.random(2,6)
enemies.insert(enemies,enemy)
enemy.enterFrame = moveEnemy
Runtime:addEventListener('enterFrame',enemy)
end
function moveEnemy(self,event)
--if self.x < 100 then
---self:removeSelf()
--self = nil
--removeSelf()
--else
self.x = self.x-self.speed
--end
end
function update(e)
if(enemies.numChildren ~= 0)then
for i = 1,enemies.numChildren do
if(enemies[i] ~= nil)then
--enemies[i].x = enemies[i].x-3
if(enemies[i].x<100)then
--enemies:remove(enemies[i])
--display.remove(enemies[i])
--enemies[i] = nil
end
end
end
end
end
I have commented out the parts that give me errors.
Any help would be appreciated,
thanks
You might want to try and put the delete code in it's own function and then use a timer to remove it so that the function where you are currently deleting the object can return and you're not deleting yourself.
Another option would be to make it temporarily invisible and then loop through the table periodically and remove anything outside of the move handler.
You have a problem with the following code:
function listeners(action)
if(action == 'add') then
Runtime:addEventListener('enterFrame',update)
enemyTimer = timer.performWithDelay(800,addEnemy,0)
else
Runtime:removeEventListener('enterFrame',update)
timer.cancel(enemyTimer)
end
end
You only want to Runtime:addEventListener('enterFrame', update) once. If you do it everytime you add an enemy things will go wrong. The problem is your code runs again and again after the objects have been removed already.
hmmm. did you use the scene template? if so, you should only put the :removeself () and = nil values in the scene destroy section at the bottom. you also dont need the second removeself that is not attached to an object as that is probably the nil issue.
to summarize.
1-put all remove self () and = nil at the destroy section of scene template and use object.isVisible = false instead.
2-the nil error is most likely coming from the removeself() statement with no object. so change it to moveenemy:removeself ()
if my understanding is right this is how i would do it without using runtime
and using timer instead. ask away if you have question
local scrWidth = display.actualContentWidth
local scrHeight = display.actualContentHeight
local enemy = {} --this will hold your aliens
function addEnemy()
enemy[#enemy + 1] = display.newImage("drone.png")
enemy[#enemy].x = 500
enemy[#enemy].y = math.floor(math.random()*300)
enemy[#enemy]:scale(-0.1,0.1)
enemy[#enemy].speed = math.random(2,6)
end
local function update()
addEnemy()
--this will move the enemy to the left from right
for i=1,#enemy,1 do
enemy[i].x = enemy[i].x - enemy[i].speed
end
--the below codes will destroy each enemy that is out side the screen on the left
local function destroyWhenOutside()
for i=1,#enemy,1 do
if enemy[i].x < 0 - enemy[i].width then
enemy[i]:removeSelf()
enemy[i] = nil
elseif enemy[i].y < 0 - enemy[i].height then
enemy[i]:removeSelf()
enemy[i] = nil
end
end
end
destroyWhenOutside()
end
--this will loop the update every 1/1000 seconds
local timerUpdate = timer.performWithDelay(1,update,-1)
.