I have a table full of different villages and their commodities, and the stock, buying, and selling price they have.
The table looks like this:
stocks = {
village = {
fish = {
12,
76,
0
},
silver = {
0,
220,
0
},
stone = {
0,
200,
0
},
silk = {
4,
1100,
0
},
salt = {
0,
10,
0
},
wood = {
23,
0,
49
}
},
}
It has three numbers in the commodity table, the first being the amount they have in stock (useful since if I'm comparing prices, i'd only want it to count if there were some in stock to buy!), second is the price they are buying for (higher the better), and the third the price they're selling it for (lower the better, and this is where stock comes in handy, being more than 0). I've tortured myself trying to come up with ways to make a nice function (like so, prices("fish")) that, when given a commodity to look for, will find the best places to buy and sell to make a profit.
The coding language I'm using to do this is Lua but I'm sure this could be done in many languages with the know-how ^_^
If someone could point me in the right direction here then I'd be forever greatful!
Here's a direction...
local function prices(commodity)
for placeName, placeData in pairs(stocks) do
local data = placeData[commodity]
if (data) then
print(placeName .. " has " .. data[1].. " " .. commodity)
-- ...
end
end
-- ...
end
I'm not clear on what results you're after but the above is one way to dig into the data structure.
Related
So, what i am trying to do is... well it's best to show. oh and This is with Fivem and trying to modify an existing resource, but...
`BMProducts = {
{
["lostItems"] = {
[1] = { name = "weapon_shotgun", price = 1500, crypto = 2500, amount = 1 },
},
}
}
table.insert(BMProducts, {
["ballasItems"] = {
[1] = { name = "weapon_pistol", price = 1500, crypto = 2500, amount = 1 },
},
})
Config.Products = BMProducts`
And I have a another config, that i need to pull the Correct table, but now sure entirely how
`["products"] = Config.Products["ballasItems"],`
Is what I have but it won't read it, due to what I assume is what i saw when debugging, that when inserting to the table, it assigns a number, ie;
[1] = {lostitems = {... [2] = {ballasItems = {...
One that works, but what my ultimate goal is to make the code plug and play with the table inserts, is this
`BMProducts =
{
["lostItems"] = {
[1] = { name = "weapon_pistol", price = 1500, crypto = 2500, amount = 1 },
},
["ballasItems"] = {
[1] = { name = "weapon_pistol", price = 1500, crypto = 2500, amount = 1 },
},
}`
which works with the config above because the way just above does not assign numbers and not inserting into a table. Any ideas how i can go about setting that config for the correct Products table?
When i try it with the table insert, and with the
`["products"] = Config.Products["ballasItems"],`
It can't find the table, which is due to what i assume the table format being different than what it was, which was the code block at the bottom
so my main thing, is to get
`["products"] = Config.Products["ballasItems"],`
to = the correct table when there is a table insert.
If you don't want to table.insert, then don't table.insert:
BMProducts["ballasItems"] = {
{ name = "weapon_pistol", price = 1500, crypto = 2500, amount = 1 },
}
Now I think you told to not modify the config, so another approach is to just use that additional array index when indexing:
["products"] = Config.Products[2]["ballasItems"]
Which obviously assumes that the config never changes and the entry with ballasItems is on index 2.
If you do not know the index, you may want to iterate over Config.Products and look for the right product.
for i,v in ipairs(Config.Products) do
if v["ballasItems"] then
end
end
You may also consider the case where two or more products match.
I have the following table
scavenging =
{
{
type = "Greenskin|16",
fast_levelup = 20, --Number of levels with 75% chance to level up after required level
normal_levelup = 40, --Number of levels with 50% chance to level up after fast_levelup + required level
slow_levelup = 40, --Number of levels with 25% chance
drops = --Drops
{
{items = {"Linen", "Bolt of Linen", "Coarse Thread", "Feather", "Cotton"}, droprates = {60, 10, 10, 10, 2}},
},
},
}
This is one data value in a series. I use
function scavenge_meta(scavenge_name)
for _, meta in pairs(scavenging) do
if string.match(meta.type, scavenge_name) then
return meta
end
end
end
to pull the needed data. The question is, is there an easy way to get to the droprates value without having to do a few for (pairs)? Right now for example I can use:
local founditem = scavenge_meta("Greenskin|16")
And this works, and then I can use founditem.fast_levelup etc. I was hoping to access the drops table with founditem.drops.items for example, but this doesn't work, I need to do a pairs(founditem.drops) then pairs(valuefound.items) /etc.
Maybe there is a better way of doing this?
if you can change the table then do:
scavenging =
{
["Greenskin|16"] = {
type = "Greenskin|16",
fast_levelup = 20,
normal_levelup = 40,
slow_levelup = 40,
drops =
{
{items = {"Linen", "Bolt of Linen", "Coarse Thread", "Feather", "Cotton"}, droprates = {60, 10, 10, 10, 2}},
},
},
}
and get data directly by index
print(scavenging["Greenskin|16"].fast_levelup)
otherwise, just by searching as you did.
This is my first attempt to use Lua tables and I'm getting on with it quite well. I'm struggling with one thing though, heres (a small sample of) my table as it currently stands:
objects = {
["1/1/1"] = { tl = 1, startVal = 1, stopVal = 0 },
["1/1/2"] = { tl = 11, startVal = 1, stopVal = 0 },
["1/1/3"] = { tl = 22, startVal = 1, stopVal = 0 },
["1/1/4"] = { tl = 33, startVal = 1, stopVal = 0 },
}
The typical operation of this is that I use the "1/1/1" values as a lookup to the inner tables and then use those values in various functions. This all works well. Now, I need to go the other way, say I have tl = 22 coming in, I want to return the top value ("1/1/3" in this case).
I think I need to do something with the inpairs I keep seeing on the web but I'm struggling to implement. Any help would be massively appreciated.
You can't use ipairs because your table is an associated array not a sequence, so you have to use pairs. Also, there is no search function builtin to Lua, so you have to loop over all items yourself, looking for the right field value:
function findTL(tbl)
for key, data in pairs(tbl) do
if data.tl == tlSearch then
return key
end
end
end
local key = findTL(objects, 22)
If you want something a tad more object-oriented you could do this:
objects.findTL = findTL -- ok because first arg is the table to search
local key = objects:findTL(22)
isn't it better to take the value directly?
objects.1/1/1.tl
I don't know if it will work also with slashes, but if not, you may replace it by 'x' for example. Then it will be:
objects.1x1x1.tl
I'm writing a game using Corona SDK in lua language. I'm having a hard time coming up with a logic for a system like this;
I have different items. I want some items to have 1/1000 chance of being chosen (a unique item), I want some to have 1/10, some 2/10 etc.
I was thinking of populating a table and picking a random item. For example I'd add 100 of "X" item to the table and than 1 "Y" item. So by choosing randomly from [0,101] I kind of achieve what I want but I was wondering if there were any other ways of doing it.
items = {
Cat = { probability = 100/1000 }, -- i.e. 1/10
Dog = { probability = 200/1000 }, -- i.e. 2/10
Ant = { probability = 699/1000 },
Unicorn = { probability = 1/1000 },
}
function getRandomItem()
local p = math.random()
local cumulativeProbability = 0
for name, item in pairs(items) do
cumulativeProbability = cumulativeProbability + item.probability
if p <= cumulativeProbability then
return name, item
end
end
end
You want the probabilities to add up to 1. So if you increase the probability of an item (or add an item), you'll want to subtract from other items. That's why I wrote 1/10 as 100/1000: it's easier to see how things are distributed and to update them when you have a common denominator.
You can confirm you're getting the distribution you expect like this:
local count = { }
local iterations = 1000000
for i=1,iterations do
local name = getRandomItem()
count[name] = (count[name] or 0) + 1
end
for name, count in pairs(count) do
print(name, count/iterations)
end
I believe this answer is a lot easier to work with - albeit slightly slower in execution.
local chancesTbl = {
-- You can fill these with any non-negative integer you want
-- No need to make sure they sum up to anything specific
["a"] = 2,
["b"] = 1,
["c"] = 3
}
local function GetWeightedRandomKey()
local sum = 0
for _, chance in pairs(chancesTbl) do
sum = sum + chance
end
local rand = math.random(sum)
local winningKey
for key, chance in pairs(chancesTbl) do
winningKey = key
rand = rand - chance
if rand <= 0 then break end
end
return winningKey
end
Being fairly new to Stata, I'm having a difficulty figuring out how to do the following:
I have time-series data on selling price (p) and quantity sold (q) for 10 products in a single datafile (i,e., 20 variables, p01-p10 and q01-q10). I am strugling with appropriate stata command that computes sales revenue (pq) time-series for each of these 10 products (i.e., pq01-pq10).
Many thanks for your help.
forval i = 1/10 {
local j : display %02.0f `i'
gen pq`j' = p`j' * q`j'
}
A standard loop over 1/10 won't get you the leading zero in 01/09. For that we need to use an appropriate format. See also
#article {pr0051,
author = "Cox, N. J.",
title = "Stata tip 85: Looping over nonintegers",
journal = "Stata Journal",
publisher = "Stata Press",
address = "College Station, TX",
volume = "10",
number = "1",
year = "2010",
pages = "160-163(4)",
url = "http://www.stata-journal.com/article.html?article=pr0051"
}
(added later) Another way to do it is
local j = string(`i', "%02.0f")
That makes it a bit more explicit that you are mapping from numbers 1,...,10 to strings "01",...,"10".