I am currently programming a Lua script. There I would like to have a variable name which is concatenated with an increasing number.
Example: Q0001,Q0002,Q0003,...,Q9999
My following script for this is:
local rnd = math.random (0,9999)
local Text = ""
print(rnd)
if rnd > 0 and rnd < 10 then
--Add Nulls before Number and the "Q"
Text = Q000 .. rnd
elseif rnd >= 10 and rnd < 100 then
--Add Nulls before Number and the "Q"
Text = Q00 .. rnd
elseif rnd >= 100 and rnd < 1000 then
--Add Null before Number and the "Q"
Text = Q0 .. rnd
elseif rnd >= 1000 then
--Add "Q"
Text = Q .. rnd
end
print(Text)
Logically I put this into a function, because its only a part of my programm. Later in the programm I like to get informations with the variable, because the product of the variable Q### is a table which I have programmed. My second thought to solve the problem was to convert it as a text, but then I don't know how to convert this into a declaration.
Edit 04/04/15 19:17: Too make it more clear. I want that Text stands after the end of the script for a table I set before. So that I can say Text.Name e.g.
Use string.format with padded format specifiers:
Just a single line:
Text = ("Q%04d"):format( rnd )
-- same as Text = string.format( "Q%04d", rnd )
Instead of creating so many tables, use a single table with the above values as keys/indexes:
t = {
Q0001 = "something",
Q0002 = "something",
Q0013 = "something",
Q0495 = "something",
-- so on
}
Related
This is my code
local level = 5
for i = 1, level do
local text = ""
for j = 1, i do
text = text..""
end
for j = 1, level-i, 1 do
text = text.." "
end
for j = 1+level, level+(level-i) do
text = text.." "
end
for j = 1, level + i-level do
text = text..""
end
print(text)
end
I want the result to be similar to the one in the picture.
Here is what your code looks like with proper formatting.
local level = 5
for i = 1, level do
local text = ""
for j = 1, i do
text = text..""
end
for j = 1, level-i, 1 do
text = text.." "
end
for j = 1+level, level+(level-i) do
text = text.." "
end
for j = 1, level + i-level do
text = text..""
end
print(text)
end
Your current code prints... well... an empty string. You haven't yet added the characters it's to display to be on par with the image.
The amount of characters per row is 9. So you ideally need 9 characters per row. You will also be incrementing the number once per row. The amount of characters per row also increases by 2; one on each side.
We can use the string.rep(string, number) function to duplicate a 'string' 'number' times. You can feed in your current level into that so it generates 1 2 or 3 depending on the line the number of times. Then you have whitespace to worry about. You can use string.rep again along with a bit of distance math to calculate the amount of whitespace you need from what you take up. Then finally throw everything together concatenated trailing with the first string and print.
local levels = 5
local columns = 9
for i=1, levels do
local str = string.rep(i, i)
local padding = columns - (#str * 2) + 1
print(str .. string.rep(" ", padding) .. str)
end
I'm having problem returning spesific amount of decimal numbers from this function, i would like it to get that info from "dec" argument, but i'm stuck with this right now.
Edit: Made it work with the edited version bellow but isn't there a better way?
local function remove_decimal(t, dec)
if type(dec) == "number" then
for key, num in pairs(type(t) == "table" and t or {}) do
if type(num) == "number" then
local num_to_string = tostring(num)
local mod, d = math.modf(num)
-- find only decimal numbers
local num_dec = num_to_string:sub(#tostring(mod) + (mod == 0 and num < 0 and 3 or 2))
if dec <= #num_dec then
-- return amount of deciamls in the num by dec
local r = d < 0 and "-0." or "0."
local r2 = r .. num_dec:sub(1, dec)
t[key] = mod + tonumber(r2)
end
end
end
end
return t
end
By passing the function bellow i want a result like this:
result[1] > 0.12
result[2] > -0.12
result[3] > 123.45
result[4] > -1.23
local result = remove_decimal({0.123, -0.123, 123.456, -1.234}, 2)
print(result[1])
print(result[2])
print(result[3])
print(result[4])
I tried this but it seems to only work with one integer numbers and if number is 12.34 instead of 1.34 e.g, the decimal place will be removed and become 12.3. Using other methods
local d = dec + (num < 0 and 2 or 1)
local r = tonumber(num_to_string:sub(1, -#num_to_string - d)) or 0
A good approach is to find the position of the decimal point (the dot, .) and then extract a substring starting from the first character to the dot's position plus how many digits you want:
local function truncate(number, dec)
local strnum = tostring(number)
local i, j = string.find(strnum, '%.')
if not i then
return number
end
local strtrn = string.sub(strnum, 1, i+dec)
return tonumber(strtrn)
end
Call it like this:
print(truncate(123.456, 2))
print(truncate(1234567, 2))
123.45
1234567
To bulk-truncate a set of numbers:
local function truncate_all(t, dec)
for key, value in pairs(t) do
t[key] = truncate(t[key], dec)
end
return t
end
Usage:
local result = truncate_all({0.123, -0.123, 123.456, -1.234}, 2)
for key, value in pairs(result) do
print(key, value)
end
1 0.12
2 -0.12
3 123.45
4 -1.23
One could use the function string.format which is similar to the printf functions from C language. If one use the format "%.2f" the resulting string will contain 2 decimals, if one use "%.3f" the resulting string will be contain 3 decimals, etc. The idea is to dynamically create the format "%.XXXf" corresponding to the number of decimal needed by the function. Then call the function string.format with the newly created format string to generate the string "123.XXX". The last step would be to convert back the string to a number with the function tonumber.
Note that if one want the special character % to be preserved when string.format is called, you need to write %%.
function KeepDecimals (Number, DecimalCount)
local FloatFormat = string.format("%%.%df", DecimalCount)
local String = string.format(FloatFormat, Number)
return tonumber(String)
end
The behavior seems close to what the OP is looking for:
for Count = 1, 5 do
print(KeepDecimals(1.123456789, Count))
end
This code should print the following:
1.1
1.12
1.123
1.1235
1.12346
Regarding the initial code, it's quite straight-forward to integrate the provided solution. Note that I renamed the function to keep_decimal because in my understanding, the function will keep the requested number of decimals, and discard the rest.
function keep_decimal (Table, Count)
local NewTable = {}
local NewIndex = 1
for Index = 1, #Table do
NewTable[NewIndex] = KeepDecimal(Table[Index], Count)
NewIndex = NewIndex + 1
end
return NewTable
end
Obviously, the code could be tested easily, simply by copy and pasting into a Lua interpreter.
Result = keep_decimal({0.123, -0.123, 123.456, -1.234}, 2)
for Index = 1, #Result do
print(Result[Index])
end
This should print the following:
0.12
-0.12
123.46
-1.23
Edit due to the clarification of the need of truncate:
function Truncate (Number, Digits)
local Divider = Digits * 10
local TruncatedValue = math.floor(Number * Divider) / Divider
return TruncatedValue
end
On my computer, the code is working as expected:
> Truncate(123.456, 2)
123.45
I’m writing power (watts) values to a text file in order to extract information I can use.
4.7
4.7
4.8
5.2
5.1
4.6
4.6
4.6
Currently I have the following code to give me the average, but I’d like to add to it so it tells me more such as, what was the highest value, the lowest value, the most frequent value, and if at all possible if there are any ‘0’ values recorded (* - if possible with that last one it would be good to ignore them..)
local ctr = 0
local sum = 0
for _ in io.lines"/www/EnergyPlug-b.txt" do
ctr = ctr + 1
end
print(ctr)
for line in io.lines"/www/EnergyPlug-b.txt" do
sum = sum + line
end
print(sum)
average = sum / ctr
print(average)
I did explore creating a Lua table via table.insert() off of the first io.lines section, like the following, but I’m not sure how good it is?
local rows = {}
-- go over the file line by line
for line in io.lines("/www/EnergyPlug-b.txt") do
-- if line matches ?.? then insert into table
local value = line:match("%d%p%d") -- 1.5
--print(value)
table.insert(rows, value)
end
local arraymax = math.max(unpack(rows))
local arraymin = math.min(unpack(rows))
print (arraymax) -- ?.?
print (arraymin) -- ?.?
If the above is suitable, how best should I go about identifying the items/values i mentioned at the very start ?
In the first snippet there is no reason to have a separate loop for ctr and sum. You can do it in one loop.
Your second snipped is ok. unpack is limited so this won't work for many thousand values.
You have to traverse the table anyway to get the other values so you can determin min and max in that loop too without that size limit.
local value = line:match("%d%p%d") if there are only those numbers in that file you can skip the pattern matching here.
The calculations are pretty straigt forward. I'm not sure what you're struggling with here.
local min = math.huge -- use a value that is definitely bigger than any value
local max = -math.huge -- use a value that is definitely smaller than any value
local counts = {} -- an emtpy table we'll use to count how often each value occurs
local numIngored = 0 -- how many 0 values have we ignored?
for line in io.lines(yourFileName) do
-- convert string to a number
local value = tonumber(line)
-- if we take the value into account
if value ~= 0.0 then
-- update min and max values
min = value < min and value or min
max = value > max and value or max
-- update counts
counts[value] = counts[value] and counts[value] + 1 or 1
else
-- count ignored values
numIgnored = numIgnored + 1
end
end
I'll leave it up to you to get the most frequent values from counts
Thanks to #piglet and using other SO posts, here is what I ended up with..
local min = math.huge -- use a value that is definitely bigger than any value
local max = -math.huge -- use a value that is definitely smaller than any value
local ctr = 0
local valtotal = 0
local counts = {} -- an emtpy table we'll use to count how often each value occurs
local numIngored = 0 -- how many 0 values have we ignored?
for line in io.lines("/www/EnergyPlug-b.txt") do
-- convert string to a number
local value = tonumber(line)
-- if we take the value into account
if value ~= 0.0 then
ctr = ctr + 1
valtotal = valtotal + value
-- update min and max values
min = value < min and value or min
max = value > max and value or max
-- update counts
counts[value] = counts[value] and counts[value] + 1 or 1
else
-- count ignored values
numIgnored = numIgnored + 1
end
end
print("----Table print out -----")
for k, v in pairs(counts) do
print(k,v)
end
print("---------------------------")
print("Lowest value recorded = " ..min)
print("Highest value recorded = " ..max)
print("Average value recorded = " ..round2(valtotal / ctr, 1))
print("Number of values recorded = " ..ctr)
print("---------------------------")
local max_val, key1 = -math.huge
for k, v in pairs(counts) do
if v > max_val then
max_val, key1 = v, k
end
end
local min_val, key2 = math.huge
for k1, v1 in pairs(counts) do
if v1 < min_val or v1 == min_val then
min_val, key2 = v1, k1
end
end
local min_qty, max_qty = 0, 0
local min_str, max_str = "", ""
for k2, v2 in pairs(counts) do
if v2 == min_val then
min_qty = min_qty + 1
min_str = min_str .. " " .. k2
elseif v2 == max_val then
max_qty = max_qty + 1
max_str = max_str .. " " .. k2
end
end
if min_qty == 1 then
print("Least recorded value was = " ..key2.. " recorded "..min_val.." times")
else
print("Least recorded values were = " ..min_str.. " each recorded "..min_val.." time")
end
if max_qty == 1 then
print("Most recorded value was = " ..key1.. " recorded "..max_val.." times")
else
print("Least recorded values were = " ..max_str.. " each recorded "..max_val.." time")
end
print("---------------------------")
I am new to programming in LUA. And I am not able to solve this question below.
Given a number N, generate a star pattern such that on the first line there are N stars and on the subsequent lines the number of stars decreases by 1.
The pattern generated should have N rows. In every row, every fifth star (*) is replaced with a hash (#). Every row should have the required number of stars (*) and hash (#) symbols.
Sample input and output, where the first line is the number of test cases
This is what I tried.. And I am not able to move further
function generatePattern()
n = tonumber(io.read())
i = n
while(i >= 1)
do
j = 1
while(j<=i)
do
if(j<=i)
then
if(j%5 == 0)
then
print("#");
else
print("*");
end
print(" ");
end
j = j+1;
end
print("\n");
i = i-1;
end
end
tc = tonumber(io.read())
for i=1,tc
do
generatePattern()
end
First, just the stars without hashes. This part is easy:
local function pattern(n)
for i=n,1,-1 do
print(string.rep("*", i))
end
end
To replace each 5th asterisk with a hash, you can extend the expression with the following substitution:
local function pattern(n)
for i=n,1,-1 do
print((string.rep("*", i):gsub("(%*%*%*%*)%*", "%1#")))
end
end
The asterisks in the pattern need to be escaped with a %, since * holds special meaning within Lua patterns.
Note that string.gsub returns 2 values, but they can be truncated to one value by adding an extra set of parentheses, leading to the somewhat awkward-looking form print((..)).
Depending on Lua version the metamethod __index holding rep for repeats...
--- Lua 5.3
n=10
asterisk='*'
print(asterisk:rep(n))
-- puts out: **********
#! /usr/bin/env lua
for n = arg[1], 1, -1 do
local char = ''
while #char < n do
if #char %5 == 4 then char = char ..'#'
else char = char ..'*'
end -- mod 5
end -- #char
print( char )
end -- arg[1]
chmod +x asterisk.lua
./asterisk.lua 15
Please do not follow this answer since it is bad coding style! I would delete it but SO won't let me. See comment and other answers for better solutions.
My Lua print adds newlines to each printout, therefore I concatenate each character in a string and print the concatenated string out afterwards.
function generatePattern()
n = tonumber(io.read())
i = n
while(i >= 1)
do
ouput = ""
j = 1
while(j<=i)
do
if(j%5 == 0)
then
ouput=ouput .. "#";
else
ouput=ouput .. "*";
end
j = j+1;
end
print(ouput);
i = i-1;
end
end
Also this code is just yours minimal transformed to give the correct output. There are plenty of different ways to solve the task, some are faster or more intuitive than others.
I need Help adding a if clause to my Change Maker, so that if say I have denominations of coins that can't equal the input coin value. For Example I have Coins worth 2,4,6 and I have a Value of 1. I Want it to return Change Not Possible I tried adding a clause to it below but when I test it I get 1.#INF
I also am curious how I can find the optimal coin solution, So on top of saying the minimum number of coins it returns the optimal coin setup if there is one.
function ChangeMaking(D,n)
--[[
//Applies dynamic programming to find the minimum number of coins
//of denominations d1< d2 < . . . < dm where d1 = 1 that add up to a
//given amount n
//Input: Positive integer n and array D[1..m] of increasing positive
// integers indicating the coin denominations where D[1]= 1
//Output: The minimum number of coins that add up to n
]]
F = {} -- F is List Array of Coins
m = tablelength(D)
F[0] = 0
for i =1,n do
temp = math.huge
j = 1
while j <= m and i >= D[j] do
temp = math.min(F[ i - D[j] ], temp)
j = j + 1
end
F[i] = temp + 1
end
--I wanted to Catch the failed Solution here but I return 1.#INF instead
--if F[n] <= 0 and F[n] == 1.#INF then print("No Change Possible") return end
return F[n]
end
function main()
--[[
//Prints a Greeting, Asks for Denominations separated by spaces.
// Iterates through the input and assigns values to table
// Table is then input into ChangeMaker, and a while loop takes an n value for user input.
// User Enters 0 to end the Loop
]]
io.write("Hello Welcome the to Change Maker - LUA Edition\nEnter a series of change denominations, separated by spaces: ")
input = io.read()
deno = {}
for num in input:gmatch("%d+") do table.insert(deno,tonumber(num)) end
local i = 1
while i ~= 0 do
io.write("Please Enter Total for Change Maker, When Finished Enter 0 to Exit: ")
input2 = io.read("*n")
if input2 ~= 0 then io.write("\nMinimum # of Coins: " .. ChangeMaking(deno,input2).."\n") end
if input2 == 0 then i=0 print("0 Entered, Exiting Change Maker") end
end
end
function tablelength(T)
--[[
//Function for grabbing the total length of a table.
]]
local count = 0
for _ in pairs(T) do count = count + 1 end
return count
end
main()