Add to table only 10 values - lua

Question

How i can add to table only max 10 users ?
Because i saving scoretbl in txt, and this file have more 100 lines :/ So i want save only 10 users.
I don't know how can i check there is username in the table, and don't add this user or not this username in the table and add it?
Example:
local scoretbl = {}
local num = 0
for i=1, 10 do
table.insert(scoretbl,{'Name '..i, 100 + num})
num = num + 100
end
local function AddToTable(name, score)
if table.HasValue(scoretbl,name) then return end // hmm its not work ?
table.insert(scoretbl,{name, score})
end
AddToTable('User 55', 5454)// 11 user
AddToTable('User 55', 5454)// check: only one username in table
AddToTable('User 32', 5454)// 12 user
local function ShowOnly10()
table.sort( scoretbl, function( a, b ) return a[2] > b[2] end )
//table.remove(scoretbl,#scoretbl) remove last index in table, if i need only 10 value, i need delete in cycle ?
for k, v in pairs(scoretbl) do
print(k ,v[1], v[2])
end
end
ShowOnly10()
// upd: maybe its fix username ?
local function AddToTable(name, score)
for k, v in pairs(scoretbl) do
if v[1] == name then return false end
end
table.insert(scoretbl,{name, score})
end

Answer 1

I recommend that you make use of Lua's hashtable, v.name and v.score are easier to read than v[1] and v[2].
The function table.HasValue does not exist. You have to write your own.
When you want to print only the first ten elements, you should only iterate over the first ten (or up to the length of the table if it is less than ten elements long).
Line comments in Lua start with --, not //.
local scoretbl = {}
for i = 1,10 do
table.insert(scoretbl, { name = 'Name '..i, score = 100*i })
end
local function AddToTable(name, score)
-- Walk the whole table to find whether a name exists
for i,v in ipairs(scoretbl) do
if v.name == name then
-- if the record is present, update it
scoretbl[i].score = score
return
end
end
-- Insert new record
table.insert(scoretbl, { name = name, score = score })
end
AddToTable('User 55', 5454) -- 11 users
AddToTable('User 55', 5454) -- check: only one username in table
AddToTable('User 32', 5454) -- 12 users
local function ShowOnly10()
table.sort(scoretbl,function(a,b) return a.score > b.score end)
for i = 1,math.min(#scoretbl,10) do
print(i, scoretbl[i].name, scoretbl[i].score)
end
end
ShowOnly10()