Here is my code:
test_tab1={}
test_tab2={}
actual={}
actual.nest={}
actual.nest.a=10
test_tab1=actual.nest
print("test_tab1.a:" .. test_tab1.a) -- prints test_tab1.a equal to 10
actual.nest.a=20
test_tab2=actual.nest
print("test_tab2.a:" .. test_tab2.a) -- prints test_tab2.a equal to 20
print("test_tab1.a:" .. test_tab1.a) -- prints test_tab1.a equal to 20
Actual Output:
test_tab1.a:10
test_tab2.a:20
test_tab1.a:20
As per my understanding both test_tab1 and test_tab2 are pointing to same address i.e actual.nest so when I am assigning actual.nest.a=20 value of test_tab1.a is also changing to 20 which was 10 previosuly.
Expected Output:
test_tab1.a:10
test_tab2.a:20
test_tab1.a:10
Can anyone help me getting this output?.If i am changing actual.nest.a=20 second time it should not reflect in test_tab1.a i.e 10
You'll have to do a copy/clone of the tables from source to destination. Doing t1 = t2 just assigns t1 the address of t2 to t1.
Here's a copy of shallow copy method you can use:
function shallowcopy(orig)
local orig_type = type(orig)
local copy
if orig_type == 'table' then
copy = {}
for orig_key, orig_value in pairs(orig) do
copy[orig_key] = orig_value
end
else -- number, string, boolean, etc
copy = orig
end
return copy
end
actual={}
actual.nest={}
actual.nest.a=10
test_tab1 = shallowcopy(actual.nest)
print("test_tab1.a:" .. test_tab1.a) -- prints test_tab1.a equal to 10
actual.nest.a = 20
test_tab2 = shallowcopy(actual.nest)
print("test_tab2.a:" .. test_tab2.a) -- prints test_tab2.a equal to 20
print("test_tab1.a:" .. test_tab1.a) -- prints test_tab1.a equal to 20
Related
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("---------------------------")
Failed Spacing
I'm trying to get all of these names with a max char of 31 to line up all together in the same row by adding the number of spaces per player name that it needs. I've been trying to accomplish this for some time now and I just can't figure this out completely.
This is my current code which is a disaster I know..
local c = client.GetPlayerNameByIndex(i)
if c ~= nil and client.GetPlayerNameByIndex(i) ~= "nil" then
playerlist[i] = all_trim(client.GetPlayerNameByIndex(i))
local leve = 67
local namelength = #client.GetPlayerNameByIndex(i) --max 31 chars
local output = "" .. client.GetPlayerNameByIndex(i)
local newspace = ""
local neededspaces = 31 - #client.GetPlayerNameByIndex(i)
print(neededspaces)
for i=1, 31-#string.sub(client.GetPlayerNameByIndex(i), 1, 31) do
newspace = newspace .. " "
end
playerinfolist[i] = output .. newspace .. "a"
end
In simple terms I want all of the "a"s to line up with each string. Thanks for helping me!
local t = "{{2173,1},{2160,5}}"
print(#t) -- 19?? wrong
How to convert to appear in numbers?
local t = {{2173,1},{2160,5}}
print(#t) -- 2 correct
You can run the string through load or loadstring (depending on your Lua version), which will return the table you are looking for:
local t = "{{2173,1},{2160,5}}"
t = (loadstring or load)("return "..t)()
print(#t) -- 2
Here is an ad hoc solution for the input you gave:
local s = "{{2173,1},{2160,5}}"
local t = {}
local n = 0
for a,b in s:gmatch("(%d+),(%d+)") do
n = n + 1
t[n] = {a,b}
end
for k,v in ipairs(t) do print(k,v[1],v[2]) end
The following script finds prime numbers in a range from 1 to 13.
When I explicitly iterate over the table that contains the results I can see that the script works as expected. However, if I use unpack() function on the table only the first 3 numbers get printed out.
From docs: unpack is "a special function with multiple returns. It receives an array and returns as results all elements from the array, starting from index 1".
Why is it not working in the script below?
t = {}
for i=1, 13 do t[i] = i end
primes = {}
for idx, n in ipairs(t) do
local isprime = true
for i=2, n-1 do
if n%i == 0 then
isprime = false
break
end
end
if isprime then
primes[idx] = n
end
end
print('loop printing:')
for i in pairs(primes) do
print(i)
end
print('unpack:')
print(unpack(primes))
Running
$ lua5.3 primes.lua
loop printing:
1
2
3
5
7
13
11
unpack:
1 2 3
Change
primes[idx] = n
to
primes[#primes+1] = n
The reason is that idx is not sequential as not every number is a prime.