I have 2 functions in Lua which create a dictionary table and allow to check if a word exists:
local dictTable = {}
local dictTableSize = 0
function buildDictionary()
local path = system.pathForFile("wordlist.txt")
local file = io.open( path, "r")
if file then
for line in file:lines() do
dictTable[line] = true
dictTableSize = dictTableSize + 1
end
io.close(file)
end
end
function checkWord(word)
if dictTable[word] then
return(true)
else
return(false)
end
end
Now I want to be able to generate a couple of random words. But since the words are the keys, how can I pick some, given the dictTableSize.
Thanks
Just add a numerical index for each word to the dictionary while loading it:
function buildDictionary()
local path = system.pathForFile("wordlist.txt")
local file = io.open( path, "r")
if file then
local index = 1
for line in file:lines() do
dictTable[line] = true
dictTable[index] = line
index = index + 1
end
io.close(file)
end
end
Now you can get a random word like this:
function randomWord()
return dictTable[math.random(1,#dictTable)]
end
Side note: nil evaluates to false in Lua conditionals, so you could write checkWord like this:
function checkWord(word)
return dictTable[word]
end
Another side note, you'll get less polution of the global namespace if you wrap the dictionary functionality into an object:
local dictionary = { words = {} }
function dictionary:load()
local path = system.pathForFile('wordlist.txt')
local file = io.open( path, 'r')
if file then
local index = 1
for line in file:lines() do
self.words[line] = true
self.words[index] = line
index = index + 1
end
io.close(file)
end
end
function dictionary:checkWord(word)
return self.words[word]
end
function dictionary:randomWord()
return self.words[math.random(1,#self.words)]
end
Then you can say:
dictionary:load()
dictionary:checkWord('foobar')
dictionary:randomWord()
Probably two ways: you can keep the array with words and just do words[math.random(#words)] when you need to pick a random word (just make sure that the second one is different from the first).
The other way is to use next the number of times you need:
function findNth(t, n)
local val = next(t)
for i = 2, n do val = next(t, val) end
return val
end
This will return b for findNth({a = true, b = true, c = true}, 3) (the order is undefined).
You can avoid repetitive scanning by memoizing the results (at this point you will be better off using the first way).
this is a trade off that you have for using the word table the way you are. i would invert the word table once you load it, so that you can get references to words by index as well if you have to. something like this:
-- mimic your dictionary structure
local t = {
["asdf"] = true, ["wer"] = true, ["iweir"] = true, ["erer"] = true
}
-- function to invert your word table
function invert(tbl)
local t = {}
for k,_ in pairs(tbl) do
table.insert(t, k)
end
return t
end
-- now the code to grab random words
local idx1, idx2 = math.random(dictTableSize), math.random(dictTableSize)
local new_t = invert(t)
local word1, word2 = new_t[idx1], new_t[idx2]
-- word1 and word2 now have random words from your 'dictTable'
Related
I am trying to build a table and add to it at the end each time I get a returned value that is not already in the table. So basically what I have so far is not working at all. I'm new to LUA but not to programming in general.
local DB = {}
local DBsize = 0
function test()
local classIndex = select(3, UnitClass("player")) -- This isn't the real function, just a sample
local cifound = False
if classIndex then
if DBsize > 0 then
for y = 1, DBsize do
if DB[y] == classIndex then
cifound = True
end
end
end
if not cifound then
DBsize = DBsize + 1
DB[DBsize] = classIndex
end
end
end
Then later I'm trying to use another function to print the contents of the table:
local x = 0
print(DBsize)
for x = 1, DBsize do
print(DB[x])
end
Any help would be much appreciated
Just store a value in the table using your unique value as a key. That way you don't have to check wether a value already exists. You simply overwrite any existing keys if you have it a second time.
Simple example that stores unique values from 100 random values.
local unique_values = {}
for i = 1, 100 do
local random_value = math.random(10)
unique_values[random_value] = true
end
for k,v in pairs(unique_values) do print(k) end
Using LUA how would I convert a table such as this to all lowercase?
return {{[ [[House]] ] = [[bob]],[ [[Roof]] ] = [[steve]],[ [[Door-Knob]] ] = [[Richard]],[ [[Rug-Duty]] ] = [[mark]],},
Assuming your input table is of the following format (I've purposefully mixed upper and lower case characters in it):
test_tbl = {["HOUse"]="BOB", ["Roof"]="STEVE"}
you can write a function as follows:
function convert_table(tbl_test)
local output_table = {}
for i, v in pairs(tbl_test) do
output_table [string.lower(i)] = string.lower(v)
end
return output_table
end
and after calling it: local returned_table= convert_table(test_tbl) you can verify that all keys and values are in lowercase:
for i,v in pairs(returned_table) do
print(i,v)
end
I want to merge two strings collections in a case-insensitive manner:
string_collection1 = {"hello","buddy","world","ciao"}
string_collection2 = {"Hello","Buddy","holly","Bye", "bYe"}
merged_string_collection = merge_case_insensitive(string_collection1,string_collection2) --> {"hello","buddy","world","holly","bye","ciao"}
Here's an attempt, but it does not work...
function merge_case_insensitive(t1,t2)
t3 = {}
for _,s1 in pairs(t1) do
for _,s2 in pairs(t2) do
if string.lower(s1) == string.lower(s2) then
t3[s1] = s1
end
end
end
t4 = {}
i = 1
for s,_ in pairs(t3) do
t4[i] = string.lower(s)
i = i + 1
end
return t4
end
string_collection1 = {"hello","buddy","world","ciao"}
string_collection2 = {"Hello","Buddy","holly","Bye", "bYe"}
merged_string_collection = merge_case_insensitive(string_collection1,string_collection2)
for k,v in pairs(merged_string_collection) do print(k,v) end
It does not work because you use == to compare both strings which is case-sensitive.
You could do something like string.lower(s1) == string.lower(s2) to fix that.
Edit:
As you can't figure out the rest yourself, here's some code:
local t1 = {"hello","buddy","world","ciao"}
local t2 = {"Hello","Buddy","holly","Bye", "bYe"}
local aux_table = {}
local merged_table = {}
for k,v in pairs(t1) do
aux_table[v:lower()] = true
end
for k,v in pairs(t2) do
aux_table[v:lower()] = true
end
for k,v in pairs(aux_table) do
table.insert(merged_table, k)
end
merged_table now contains the lower case version of every word in both input tables.
Now pour that into a function that takes any number of input tables and you are done.
What we did here: we use the lower case version of every word in those tables and store them in a list. aux_table[string.lower("Hello")] will index the same value as aux_table[string.lower("hello")]. So we end up with one entry for each word, even if a word comes in multiple variations.
Using the keys saves us the hassle of comparing strings and distiguishing between unique words and others.
To get a table with all strings from two other tables appearing once (without regard to case), you need something like this:
function merge_case_insensitive(t1,t2)
local ans = {}
for _,v in pairs(t1) do ans[v:lower()] = true end
for _,v in pairs(t2) do ans[v:lower()] = true end
return ans
end
string_collection1 = {"hello","buddy","world","ciao"}
string_collection2 = {"Hello","Buddy","holly","Bye", "bYe"}
merged_string_collection = merge_case_insensitive(string_collection1,string_collection2)
for k in pairs(merged_string_collection) do print(k) end
Edit: And in case you want an array result (without adding another iteration)
function merge_case_insensitive(t1,t2)
local ans = {}
local
function add(t)
for _,v in pairs(t) do
v = v:lower()
if ans[v] == nil then ans[#ans+1] = v end
ans[v] = true
end
end
add(t1)
add(t2)
return ans
end
string_collection1 = {"hello","buddy","world","ciao"}
string_collection2 = {"Hello","Buddy","holly","Bye", "bYe"}
merged_string_collection = merge_case_insensitive(string_collection1,string_collection2)
for _,v in ipairs(merged_string_collection) do print(v) end
We can do this by simply iterations over both tables, and storing a temporary dictionary for checking what words we have already found, and if not there yet, putting them in our new array:
function Merge(t1, t2)
local found = {} --Temporary dictionary
local new = {} --New array
local low --Value to store low versions of words in later
for i,v in ipairs(t1) do --Begin iterating over table one
low = v:lower()
if not found[low] then --If not found yet
new[#new+1] = low --Put it in the new table
found[low] = true --Add it to found
end
end
for i,v in ipairs(t2) do --Repeat with table 2
low = v:lower()
if not found[low] then
new[#new+1] = low
found[low] = true
end
end
return new --Return the new array
end
This method eliminates the need for a third iteration, like in Piglet's answer, and doesn't keep redefining a function and closure and calling them like in tonypdmtr's answer.
I'm trying to get the name of all the file saved in two folders, the name are saved as :
1.lua 2.lua 3.lua 4.lua and so on
the folders name are :
first folder : "/const/"
second folder: "/virt/"
what I'm trying to do is only get the number of the files and this works but not in the right order, when I get the 17 file for example I get the 17th delivered from the function before the 15 and this causes for me a problem here the code of the function that I'm using :
local virt_path = "/virt/"
local const_path = "/const"
local fs = require "lfs"
local const = {}
for num = 1, (numberoffile)do -- numberoffile is predfined and can't be change
const[num] = assert(
dofile (const_path .. mkfilename(num)),
"Failed to load constant ".. num ..".")
end
local function file_number() --this is the function that causes me a headach
local ci, co, num = ipairs(const)
local vi, vo, _ = fs.dir(virt_path)
local function vix(o)
local file = vi(o)
if file == nil then return nil end
local number = file:match("^(%d+).lua$")
if number == nil then return vix(o) end
return tonumber(number)
end
local function iter(o, num)
return ci(o.co, num) or vix(o.vo, num)
end
return iter, {co=co, vo=vo}, num
end
As I said the function delive the need return values but not the right Arithmetic order.
any idea what I'm doing wrong here ?
I use my path[1] library.
1 We fill table with filenames
local t = {}
for f in path.each("./*.lua", "n") do
t[#t + 1] = tonumber((path.splitext(f)))
end
table.sort(t)
for _, i in ipairs(t) do
-- do work
end
2 We check if files exists
for i = 1, math.huge do
local p = "./" .. i .. ".lua"
if not path.exists(p) then break end
-- do work
end
[1] https://github.com/moteus/lua-path
I have the following string data that I receive as input:
"route1,1234,1,no~,,route2,1234,1,no~,"
It represents two "records" of data... where each record has 4 fields.
I've built code to parse this string into it's individual columns / fields.
But the part that isn't working is when I test to see if I have any duplicates in field 2. Field 2 is the one that currently has "1234" as the value.
Here's the code:
function string:split(delimiter)
local result = { }
local from = 1
local delim_from, delim_to = string.find( self, delimiter, from )
while delim_from do
table.insert( result, string.sub( self, from , delim_from-1 ) )
from = delim_to + 1
delim_from, delim_to = string.find( self, delimiter, from )
end
table.insert( result, string.sub( self, from ) )
return result
end
local check_for_duplicate_entries = function(route_data)
local route
local route_detail = {}
local result =true
local errtxt
local duplicate = false
print("received :" ..route_data)
route = string.gsub(route_data, "~,,", "~")
route = route:sub(1,string.len(route)-2)
print("route :" ..route)
-- break up in to an array
route = string.split(route,"~")
for key, value in pairs(route) do
route_detail[key] = string.split(value,",")
end
local list_of_second_column_only = {}
for key,value in pairs(route_detail) do
local temp = value[2]
print(temp .. " - is the value I'm checking for")
if list_of_second_column_only[temp] == nil then
print("i dont think it exists")
list_of_second_column_only[key] = value[2]
print(list_of_second_column_only[key])
else
--found a duplicate.
return true
end
end
return false
end
print(check_for_duplicate_entries("route1,1234,1,no~,,route2,1234,1,no~,"))
I think where I'm going wrong is the test:
if list_of_second_column_only[temp] == nil then
I think I'm checking for key with the value temp instead of a value with the value that temp contains. But I don't know how to fix the syntax.
Also, I'm wondering if there's a more efficient way to do this.
The number of "records" i receive as input is dynamic / unknown, as is the value of the second column in each record.
Thanks.
EDIT 1
The post I was trying to use as a reference is: Search for an item in a Lua list
In the answer, they show how to test for a record in the table by value, instead of looping through the entire table...
if items["orange"] then
-- do something
end
I was playing around to try and do something similar...
This should be a bit more efficient with only one table creation and less regex matching.
The match does require that you're only interested in dups in the second field.
local function check_for_duplicate_entries(route_data)
assert(type(route_data)=="string")
local field_set = {}
for route in route_data:gmatch"([^~]*)~,?,?" do
local field = route:match",([^,]*)"
if field_set[field] then
return true
else
field_set[field] = true
end
end
return false
end
Try this. It's doing the check on the value of the second field.
I haven't looked at the efficiency.
if list_of_second_column_only[value[2]] == nil then
print("i dont think it exists")
list_of_second_column_only[value[2]] = true
print(list_of_second_column_only[value[2]])
else
--found a duplicate.
return true
end