Random sequance

Solar2D Lua Language
#1

I need sequance of numbers from 1 to 5 in random order, for instance 4,2,1,5,3. How to do it in Lua language? [import]uid: 32980 topic_id: 6191 reply_id: 306191[/import]

#2

math.randomseed(os.time()) – (somewhere near top of code, not in a loop)
local no = math.random(1,5)

For more info see…

http://developer.anscamobile.com/reference/index/mathrandom
http://developer.anscamobile.com/reference/index/mathrandomsed
[import]uid: 6981 topic_id: 6191 reply_id: 21246[/import]

#3

If you want each number to appear uniquely, it’s a little more work:
[lua]-- assume randomseed was set at some point

local sequence, limit = {}, – desired length of sequence
for i=1,limit do
local pos = math.random(limit)
local n = 1; repeat
if sequence[n] then pos = pos + 1 end
n = n + 1
until n >= pos
sequence[pos] = i
limit = limit - 1
end[/lua]

This should randomly distribute integer values from 1-limit across integer keys from 1-limit in the table sequence. [import]uid: 12678 topic_id: 6191 reply_id: 21570[/import]

#4

Yes, I want each number to appear uniquely. Thank you, alestane. [import]uid: 32980 topic_id: 6191 reply_id: 21653[/import]

#5

What am I doing wrong here?
[lua]local sequence, limit = {8}, – desired length of sequence
for i=1, limit do
local pos = math.random( limit )
local n = 1; repeat
if sequence[n] then pos = pos + 1 end
n = n + 1
until n >= pos
sequence[pos] = i
limit = limit - 1
end[/lua]

Terminal Reads:

Syntax error: .../RandomNumbers/main.lua:36: unexpected symbol near 'for'

Also, how do I call these 8 individual random numbers?

I want to eventually have an “if” statement that says something like:
[lua]if value == 2 then
local disp = display.newImage( “image” … randmNum … “.png”, 0, 0, true)
– I want to … randmNum … to populate on it’s own
end[/lua]

I am trying to use this as a tool to load 16 different cards for a matching game. [import]uid: 7850 topic_id: 6191 reply_id: 25292[/import]

#6

bump [import]uid: 7850 topic_id: 6191 reply_id: 39540[/import]

#7

As far as your syntax error goes, it looks like you want to change

local sequence, limit = {8},

to

local sequence, limit = {}, 8

As far as getting the table to your eventual use code, you’ll need to pass it back from a creation function, or save it as a field in some data structure, or *shudder* save it in a global variable.

Assuming that it’s still named sequence when it reaches your other code, it would look something like

[lua]for i, randmNum in ipairs(sequence) do
if value == 2 then
local disp = display.newImage( “image” … randmNum … “.png”, 0, 0, true)
end
end[/lua] [import]uid: 12678 topic_id: 6191 reply_id: 39547[/import]

#8

Use a shuffle algorithm on the table {1,2,3,4,5}

-- see: http://en.wikipedia.org/wiki/Fisher-Yates\_shuffle  
  
function shuffle(t)  
 local n = #t  
   
 while n \> 2 do  
 -- n is now the last pertinent index  
 local k = math.random(n) -- 1 \<= k \<= n  
 -- Quick swap  
 t[n], t[k] = t[k], t[n]  
 n = n - 1  
 end  
   
 return t  
end  
  
myTable = shuffle( {1,2,3,4,5} )

[import]uid: 61132 topic_id: 6191 reply_id: 39549[/import]

#9

I still can not get this to work…

There is nothing random about it :frowning:

[code]

math.randomseed( os.time() )

function shuffle(t)
local n = #t

while n > 2 do
– n is now the last pertinent index
local k = math.random(n) – 1 <= k <= n
– Quick swap
t[n], t[k] = t[k], t[n]
n = n - 1
end

return t
end

nums = shuffle({})

local sequence, limit = {},9
for i=2,limit do
local pos = math.random(limit)
local n = 1; repeat
if sequence[n] then
pos = pos + 1
end
n = n + 1
until n >= pos
sequence[pos] = i
limit = limit - 1
print ( limit )
table.insert(nums, limit)
end

print (table.concat(nums, ", ")) [/code]
OUTPUT:

8
7
6
5
4
3
2
1
8, 7, 6, 5, 4, 3, 2, 1

Anyone have any ideas?
[import]uid: 7850 topic_id: 6191 reply_id: 40376[/import]

#10

You can’t pass an empty table to a shuffle() function and expect anything good. It needs something to shuffle! Try the following:

math.randomseed( os.time() )  
   
function shuffle(t)  
 local n = #t  
   
 while n \> 2 do  
 -- n is now the last pertinent index  
 local k = math.random(n) -- 1 \<= k \<= n  
 -- Quick swap  
 t[n], t[k] = t[k], t[n]  
 n = n - 1  
 end  
   
 return t  
end  
  
nums = shuffle({1,2,3,4,5})

nums should come out with a randomized sequence.
[import]uid: 61132 topic_id: 6191 reply_id: 40377[/import]

#11

works 100% perfect!

Thanks so much for the help! [import]uid: 7850 topic_id: 6191 reply_id: 40378[/import]