How to sort an array?

[annikk.exe]

Code: [Select]

myarray = { 3, 2, 5, 1, 4 }
How do I sort this into:

Code: [Select]

myarray = { 1, 2, 3, 4, 5 }
?



Is it...

Code: [Select]

table.sort(myarray)
?

[annikk.exe]

I've developed this code:

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function Sort(ar, num)
-- sorts a 0-indexed array into order, and returns the sorted array
-- inputs are (array to be sorted, number of elements to sort)
-- typically inputs will be like: myarray = Sort(myarray, # myarray)

-- Lua is stupid and sorts tables from 1-to-arraylength instead of indexing from 0 like any sensible language
-- so we must copy the incoming array to a temporary renumbered array.
temp = {}
for i = 1,num+1 do
temp[i] = ar[i-1]
end
-- copied to temporary array
-- now sort
table.sort(temp)
-- sorted.  now copy back to real array
for i = 1,num+1 do
ar[i-1] = temp[i]
end
return ar
end
Also tonight I learned a useful feature of lua.  If you write something like:

x = # myarray

then x is now equal to the length of the array!

So for example, you can do:

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for ID = 0, # myarray
myarray[ID] = nil
end
That would find all existing entries in the array and set them to nil.

# <array> returns the length of the array.

If you have elements [0 ], [1], and [2], using # array will return 2.  If you just have elements [1] and [2] then it will still return 2.  It seems to start counting from 1..

[Pilchard123]

You can also use

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for i in ipairs(tablename) do
  //DO AWSUMZ STUFF HEER
end

to iterate over every element in an array.

[annikk.exe]

How does that work?  What is ipairs?

[Aino]

Annikk, for your 3D engine I suggest you use arrays to sort the verticles like Objects in OO programming.

It's easy to do:

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Verticles= {}

for i = 1, 40 do

Verticles[i] = {x = 0, y = 0, z = 0} -- You can have many more variables, there shouldn't be any limit except for the Memory consumption...

end

With that you can do

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Verticles[x].x = something instead of

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VerticleX[x] = something

[annikk.exe]

That's a cool technique Aino..  definitely a lot neater than vertex3dX and vertex3dY.  I might switch to that when I go back and tidy up/optimise the engine.

By the way, it's actually vertices rather than verticles.
It's pronounced like "Verr-Tiss-uz" if that makes sense... not "verr tick ulls"

[Aino]

Oh, thought it was Verticle, but mistakes are made

[annikk.exe]

Verticle is a funny name though.. :>  It makes me laugh.

[Pilchard123]

Sorry I haven't got back to you about ipairs. Exams and stuff.

Have a link it'll explain better than I will.
http://lua-users.org/wiki/TablesTutorial