local data={}
eventNewPlayer=function(n)
data[n]={tab="none"}
end
function eventChatCommand(n,c)
if c == "foo" then
data[n].tab = c
if data[n].tab == c then
ui.removeTextArea(90,n)
else
ui.addTextArea(90,"f"..string.rep("o",35),n,400,200,nil,nil)
end
end
end
table.foreach(tfm.get.room.playerList,eventNewPlayer)
It's a logical error the textarea does not appear whatsoever and I don't really see any error in the code mentioned above
When data[n].tab = c is executed, you are assigning the value of c to data[n].tab. This will happen every time that c == "foo".
Therefore, when you execute this:
if data[n].tab == c then
ui.removeTextArea(90,n)
else
ui.addTextArea(90,"f"..string.rep("o",35),n,400,200,nil,nil)
end
It will always execute the first part, and not the second part.
Related
I am trying to write a string join function that will work with both tables and variable arguments as input. Here is what I have so far:
function join(separator, ...)
local result = ""
local vargs = {...}
local n = #vargs
for i = 1, n do
local varg = vargs[i]
if type(varg) == "table" then
result = join(separator, result, table.unpack(varg))
elseif varg ~= nil then
result = result..tostring(varg)
if i < n then
result = result..separator
end
end
end
return result
end
However, when I try to use it with the following input:
print(join(",", "1", "2", "3"))
print(join(",", {"a", "b", "c"}))
The output is this:
1,2,3
,a,b,c
I did not expect the , at the beginning of a,b,c.
From what I understand, it seems somehow the separator is getting added to the variable arguments when calling the function inside the function (recursiveness). But why is that? And how can I fix it? Thank you!
Try
...
if type(varg) == "table" then
varg = join(separator, table.unpack(varg))
end
if varg ~= nil then
...
Well uh sorry if it's not really useful but maybe it's because you put the: , into "" that it print the ,
require 'class'
Paddle=class{}
function Paddle:init(x,y,width,height)
self.x=x
self.y=y
self.width=width
self.height=height
self.dy=0
end function Paddle:update(dt)
if self.dy < 0 then
self.y = math.max(`enter code here`0, self.y + self.dy * dt)
else
self.y=math.min(VIRTUAL_HEIGHT,-self.height,self.y+self.dy*dt)
end
end
function Paddle:render()
love.graphics.rectangle('fill',self.x,self.y,self.width,self.height)
end
I am following the course CS50 lecture 0 pong update 5, and the same code is working for the teacher. I don't know why this is happening neither understand the problem because it makes no sense. If you want, here's 'class'. This problem isn't happening in the other class I made called 'ball' which does exactly the same thing. I also defined self.dy, and it does have a value "0" so I don't know why it does that error and what that error means.
local function include_helper(to, from, seen)
if from == nil then
return to
elseif type(from) ~= 'table' then
return from
elseif seen[from] then
return seen[from]
end
seen[from] = to
for k,v in pairs(from) do
k = include_helper({}, k, seen) -- keys might also be tables
if to[k] == nil then
to[k] = include_helper({}, v, seen)
end
end
return to
end
-- deeply copies `other' into `class'. keys in `other' that are already
-- defined in `class' are omitted
local function include(class, other)
return include_helper(class, other, {})
end
-- returns a deep copy of `other'
local function clone(other)
return setmetatable(include({}, other), getmetatable(other))
end
local function new(class)
-- mixins
class = class or {} -- class can be nil
local inc = class.__includes or {}
if getmetatable(inc) then inc = {inc} end
for _, other in ipairs(inc) do
if type(other) == "string" then
other = _G[other]
end
include(class, other)
end
-- class implementation
class.__index = class
class.init = class.init or class[1] or function() end
class.include = class.include or include
class.clone = class.clone or clone
-- constructor call
return setmetatable(class, {__call = function(c, ...)
local o = setmetatable({}, c)
o:init(...)
return o
end})
end
-- interface for cross class-system compatibility (see https://github.com/bartbes/Class-Commons).
if class_commons ~= false and not common then
common = {}
function common.class(name, prototype, parent)
return new{__includes = {prototype, parent}}
end
function common.instance(class, ...)
return class(...)
end
end
-- the module
return setmetatable({new = new, include = include, clone = clone},
{__call = function(_,...) return new(...) end})
So this is the part where I call the update function, which is what someone said might be the error
function love.update(dt)
if love.keyboard.isDown('w') then
player1.dy=-PADDLE_SPEED
elseif love.keyboard.isDown('s') then
player1.dy=PADDLE_SPEED
else
player1.dy=0
end
if love.keyboard.isDown('up') then
player2.dy=-PADDLE_SPEED
elseif love.keyboard.isDown('down') then
player2.dy=PADDLE_SPEED
else
player2.dy=0
end
if gameState=='play' then
ball.update(dt)
end
player1.update(dt)
player2.update(dt)
This error is pretty clear on what you're doing wrong.
You're indexing local self, a number value.
That means that somewhere you're doing something like self.dy where self is not a table but a number and using the index operator . on numbers is not allowed as it does not make any sense.
The question is why self is not a table.
function myTable:myFunction() end
is short (syntactic sugar) for
function myTable.myFunction(self) end
and the function call
myTable:myFunction() is short for myTable.myFunction(myTable)
Please refer to the Lua manual.
Function Calls
Function Definitions
Find a function in your code that is defined with : and called with . and gets a number as first argument during that call.
That way a number ends up where you expect self.
I guess the error is in the main.lua which you did not provide.
There you have several calls to Paddle:update(dt). Writing myPaddle.update(dt) would cause that error for example. But I can't tell for sure as you did not provide your code.
But that it works for the teacher, but not for you is usually because you do something different/wrong.
Edit:
As you've provided more code I can tell for sure that the observed error is caused by
ball.update(dt)
player1.update(dt)
player2.update(dt)
This will put dt a number value, where the function expects self, the table ball.
replace it by
ball.update(ball, dt) or ball:update(dt)
player1.update(player1, dt) or player1:update(dt)
player2.update(player2, dt) or player2:update(dt)
Please can someone explain to me, why NOT initializing first_idx and last_idx causes the code not to run??
When I run it I get this error "undefined local variable or method last_idx". I know that the advice is to always initialize the variables, but I don't understand why. After all first_idx and last_idx will ALWAYS get a value inside the loop because the argument letter is always present in the string (in this particular problem).
I'd really appreciate some (simple) insight. Thank you!
P.S, I also know that the problem is easily solved using #index and #rindex in Ruby, but I'm not allowed to solve it using straightforward methods.
def find_for_letter(string, letter)
first_idx = nil
0.upto(string.length - 1) do |idx1|
if string[idx1] == letter
first_idx = idx1
break
end
end
last_idx = nil
(string.length - 1).downto(0) do |idx2|
if string[idx2] == letter
last_idx = idx2
break
end
end
if last_idx == first_idx
return [first_idx]
else
return [first_idx, last_idx]
end
end
def first_last_indices(word)
h = {}
word.chars.each do |char|
h[char] = find_for_letter(word, char)
end
h
end
Variables in block
From the Ruby Programming Language:
Blocks define a new variable scope: variables created within a block
exist only within that block and are undefined outside of the block.
Be cautious, however; the local variables in a method are available to
any blocks within that method. So if a block assigns a value to a
variable that is already defined outside of the block, this does not
create a new block-local variable but instead assigns a new value to
the already-existing variable.
a = 0
2.times do
a = 1
end
puts a #=> 1
b = 0
2.times do |i;b| # <- b will stay a block-local variable
b = 1
end
puts b #=> 0
2.times do |i|
c = 1
end
puts c #=> undefined local variable or method `c' for main:Object (NameError)
Refactoring your code
Iterating with chars and index
Here's a smaller method for your goal.
It keeps a hash with minmax indices for each character.
The default hash value is an empty array.
The method iterates over each character (with index).
If minmax array already contains 2 values :
it replaces the second one (max) with current index.
it adds current index to the array otherwise.
def first_last_indices(word)
minmax_hash = Hash.new { |h, k| h[k] = [] }
word.each_char.with_index do |char, index|
minmax = minmax_hash[char]
if minmax.size == 2
minmax[1] = index
else
minmax << index
end
end
minmax_hash
end
p first_last_indices('hello world')
{"h"=>[0], "e"=>[1], "l"=>[2, 9], "o"=>[4, 7], " "=>[5], "w"=>[6], "r"=>[8], "d"=>[10]}
With group_by
Here's another possibility. It uses group_by to get all the indices for each character, and minmax to get just the first and last indices :
def first_last_indices(word)
word.each_char.with_index
.group_by{ |c, _| c }.map{ |c, vs|
[c, vs.map(&:last).minmax.uniq]
}.to_h
end
p first_last_indices('hello world')
{"h"=>[0], "e"=>[1], "l"=>[2, 9], "o"=>[4, 7], " "=>[5], "w"=>[6], "r"=>[8], "d"=>[10]}
Even if you do not declare last_idx, you can still initialise it inside the loop, i.e.:
(string.length - 1).downto(0) do |idx2|
if string[idx2] == letter
last_idx = idx2 # works absolutely fine
break
end
end
However notice where you declared the variable. Its a local variable and hence its tied to the block you are in. Now when you try to access that variable outside the block, you get the error:
undefined local variable or method last_idx
To make the variable available outside the block, you have to declare it outside. That is what you are doing when you declare last_idx = nil before the block where its assigned a value.
UPDATE:
Though by using instance variables you can avoid declaration, the best practices suggests it should be used in cases where information that these variables have is relevant to all or almost all of the class. On the other hand, if the information is very much limited to this particular method use local variables.
This is just the way that local variables work.
If you use instance variables, Ruby will assume that they have been initialised inside the conditional block, but will not for local variables.
def find_for_letter(string, letter)
0.upto(string.length - 1) do |idx1|
if string[idx1] == letter
#first_idx = idx1
break
end
end
(string.length - 1).downto(0) do |idx2|
if string[idx2] == letter
#last_idx = idx2
break
end
end
if #last_idx == #first_idx
return [#first_idx]
else
return [#first_idx, #last_idx]
end
end
This works fine.
Hi I have a helper method for some calculations, I want to put some text but when I call this method the after calculation is in float.
I want to put text how can I do this?
if m == e
0.0
elsif e == 0
put "not defined"
else
(m - e)/e
end
Any idea? thanks!
if m == e
'0'
elsif e == 0
put "not defined"
else
((m - e)/e).to_s
end
Look Ruby in Twenty Minutes
Suppose your helper method name is foo
If you want to convert its return type to String for a particular method call, then method can be invoked like foo.to_s
In other places where you need the result as Float, just call it as foo .
I'm attempting to compare two tables of equal length with a function, since I don't know of any other way to do so. However, with the following function, it fails to register, and I've no clue why. I'm hoping someone can provide insight to this problem or has a better way of comparing the two tables.
The tables are being populated with the following code:
str = "parameters determined by program (all digits)"
tableone = {}
for word in str:gmatch("%d") do table.insert(tableone,word) end
It's identical for both tables, except, of course, the individual table names. The tables are being populated properly, and display properly when I print them. Here are two tables for the sake of this question:
tableone = {}
tabletwo = {}
for i=1,4 do table.insert(tableone, i) end
for i=1,4 do table.insert(tabletwo, i) end
Obviously, these two tables are going to be equal to each other. The function I wrote to compare the index tables is as follows:
function comparetables(t1, t2)
matchct = 0
for i=1,#t1 do
if t1[i] == t2[i] then
matchct = matchct + 1
end
if matchct == #t1 then
return true
end
end
I tried doing
print(comparetables(tableone,tabletwo))
to see if it'll print "true" but no luck. To me, it seems like it should work without a problem. Yet it doesn't. What am I missing? I've tried searching for something like a table.compare function that someone may have already written, but no such luck in finding one. Thanks for any suggestions!
Additional information:
The reason I'm comparing tables is for a mastermaind-type game. That means the following three rules must apply when comparing tables. The function I created was to just get me started, thinking I could work from there.
When comparing the tables, if the numbers match, Ccount increases by 1.
When comparing tables, if the value exists in a different index position, increment Pcount by 1
For example, with a table of values {1, 3, 3, 4} and a guess of {4, 4, 3, 1}, it would return Pcount of 2 (the one 4 and the 1) and a Ccount of 1 (the three in the third position). I think one of the hardest parts is going to be getting the comparison to recognize that the second 4 in the guess should not increment the Pcount at all.
A slight variant on your code that should work is:
function comparetables(t1, t2)
if #t1 ~= #t2 then return false end
for i=1,#t1 do
if t1[i] ~= t2[i] then return false end
end
return true
end
However I use something more like this: It checks the types of the arguments, their metatables, and a few other cases.
-- This is not clever enough to find matching table keys
-- i.e. this will return false
-- recursive_compare( { [{}]:1 }, { [{}]:1 } )
-- but this is unusual enough for me not to care ;)
-- It can also get stuck in infinite loops if you use it on
-- an evil table like this:
-- t = {}
-- t[1] = t
function recursive_compare(t1,t2)
-- Use usual comparison first.
if t1==t2 then return true end
-- We only support non-default behavior for tables
if (type(t1)~="table") then return false end
-- They better have the same metatables
local mt1 = getmetatable(t1)
local mt2 = getmetatable(t2)
if( not recursive_compare(mt1,mt2) ) then return false end
-- Check each key-value pair
-- We have to do this both ways in case we miss some.
-- TODO: Could probably be smarter and not check those we've
-- already checked though!
for k1,v1 in pairs(t1) do
local v2 = t2[k1]
if( not recursive_compare(v1,v2) ) then return false end
end
for k2,v2 in pairs(t2) do
local v1 = t1[k2]
if( not recursive_compare(v1,v2) ) then return false end
end
return true
end
Here's an example of it in use:
print( recursive_compare( {1,2,3,{1,2,1}}, {1,2,3,{1,2,1}} ) ) -- prints true
print( recursive_compare( {1,2,3,{1,2,1}}, {2,2,3,{1,2,3}} ) ) -- prints false
If you're comparing objects that are more objecty than tabley in an Object oriented sense, then I'd look at implementing the functions in the lua OO way.
Something like this should do the trick:
GameState = {}
GameState.mt = {}
GameState.mt.fns = {}
GameState.mt.__index = GameState.mt.fns
function GameState.new(a,b,c,d)
-- TODO: put argument checks here...
local retval = {}
retval[1] = a
retval[2] = b
retval[3] = c
retval[4] = d
setmetatable(retval, GameState.mt)
return retval
end
function GameState.mt.fns.print( self )
print(" GameState: ", self[1], self[2], self[3], self[4] )
end
function GameState.mt.__tostring( self )
return "GameState: "..self[1].." "..self[2].." "..self[3].." "..self[4]
end
function GameState.mt.__eq(self, other)
-- Check it's actually a GameState, and all its bits match
return getmetatable(other)==GameState.mt and
(self[1] == other[1]) and
(self[2] == other[2]) and
(self[3] == other[3]) and
(self[4] == other[4])
end
Then you'd use it like this:
state1 = GameState.new(1,2,3,4)
state2 = GameState.new(1,2,3,4)
print("State 1 is:")
state1:print()
print("State 2 is:")
print(state2)
print( "state1 == state2 : ", state1 == state2 )
print( "Changing state 2")
state2[1]=2
print( "state1 == state2 : ", state1 == state2 )