Sort a Table[] in Lua

Question

I have a Lua table that I am trying to sort. The table's format is as follows:

tableOfKills[PlayerName] = NumberOfKills 

Which means, for example, if I had a player named Robin with a total of 8 kills and another named Jon with a total of 10 kills, the table would be:

tableOfKills[Robin] = 8 tableOfKills[Jon]   = 10 

How would I sort that type of table to show the highest kills first? Thanks in advance!

Answer 1

A table in Lua is a set of key-value mappings with unique keys. The pairs are stored in arbitrary order and therefore the table is not sorted in any way.

What you can do is iterate over the table in some order. The basic pairs gives you no guarantee of the order in which the keys are visited. Here is a customized version of pairs, which I called spairs because it iterates over the table in a sorted order:

function spairs(t, order)     -- collect the keys     local keys = {}     for k in pairs(t) do keys[#keys+1] = k end      -- if order function given, sort by it by passing the table and keys a, b,     -- otherwise just sort the keys      if order then         table.sort(keys, function(a,b) return order(t, a, b) end)     else         table.sort(keys)     end      -- return the iterator function     local i = 0     return function()         i = i + 1         if keys[i] then             return keys[i], t[keys[i]]         end     end end 

Here is an example of use of such function:

HighScore = { Robin = 8, Jon = 10, Max = 11 }  -- basic usage, just sort by the keys for k,v in spairs(HighScore) do     print(k,v) end --> Jon     10 --> Max     11 --> Robin   8  -- this uses an custom sorting function ordering by score descending for k,v in spairs(HighScore, function(t,a,b) return t[b] < t[a] end) do     print(k,v) end --> Max     11 --> Jon     10 --> Robin   8