added todo for tablex.weighted_random, removed returning the weight value as multi-return wasn't documented and could break in some circumstances

This commit is contained in:
Max Cahill 2021-11-18 10:35:26 +11:00
parent 7aa476a58c
commit 31bfe92d37

View File

@ -202,24 +202,29 @@ function tablex.take_random(t, r)
return table.remove(t, tablex.random_index(t, r))
end
--return a random index based on weights provided
--Example: { 0.3, 1, 6, 0.5 } (3rd index most likely)
--return a random index based on weights provided (or nil if it's empty)
-- { 0.3, 1, 6, 0.5 } -> (3rd index most likely)
-- possible todo:
-- provide normalisation outside of this function, require normalised weights
-- provide table of values _and_ weights and return the value
function tablex.weighted_random(t, r)
if #t == 0 then
return nil
end
local sum = 0
for _, weight in ipairs (t) do
for _, weight in ipairs(t) do
sum = sum + weight
end
local rnd = _random(nil, nil, r) * sum
sum = 0
for i, weight in ipairs (t) do
for i, weight in ipairs(t) do
sum = sum + weight
if rnd <= sum then
return i, weight
return i
end
end
--shouldn't get here but safety if using a random that returns >= 1
return #t
end
--shuffle the order of a table