ZexisStryfe: Created page with "-- Imported from: https://runescape.wiki/w/Module:Array local libraryUtil = require('libraryUtil') local checkType = libraryUtil.checkType local checkTypeMulti = libraryUtil.checkTypeMulti ---@class Array ---@operator call(any[]): Array ---@operator concat(any[]): Array ---@operator concat(number|string|function): string ---@operator unm: Array ---@operator add(number|number[]|Array): Array ---@operator sub(number|number[]|Array): Array ---@operator mul(number|number[]..."

2023-10-14T16:00:18Z

Created page with "-- Imported from: https://runescape.wiki/w/Module:Array local libraryUtil = require('libraryUtil') local checkType = libraryUtil.checkType local checkTypeMulti = libraryUtil.checkTypeMulti ---@class Array ---@operator call(any[]): Array ---@operator concat(any[]): Array ---@operator concat(number|string|function): string ---@operator unm: Array ---@operator add(number|number[]|Array): Array ---@operator sub(number|number[]|Array): Array ---@operator mul(number|number[]..."

New page

-- Imported from: https://runescape.wiki/w/Module:Array

local libraryUtil = require('libraryUtil')
local checkType = libraryUtil.checkType
local checkTypeMulti = libraryUtil.checkTypeMulti

---@class Array
---@operator call(any[]): Array
---@operator concat(any[]): Array
---@operator concat(number|string|function): string
---@operator unm: Array
---@operator add(number|number[]|Array): Array
---@operator sub(number|number[]|Array): Array
---@operator mul(number|number[]|Array): Array
---@operator div(number|number[]|Array): Array
---@operator pow(number|number[]|Array): Array
local Array = {
pop = table.remove
}
Array.__index = Array

setmetatable(Array, {
__index = table,
__call = function (_, arr)
return Array.new(arr)
end
})

-- function Array.__tostring(arr)
-- -- local dumpObject = require('Module:Logger').dumpObject
-- require 'log'
-- local dumpObject = dumpObject
-- local mt = getmetatable(arr)
-- setmetatable(arr, nil)
-- local str = dumpObject(arr, {clean=true, collapseLimit=100})
-- setmetatable(arr, mt)
-- return str
-- end

function Array.__concat(lhs, rhs)
if type(lhs) == 'table' and type(rhs) == 'table' then
local res = {}
for i = 1, #lhs do
res[i] = lhs[i]
end
local l = #lhs
for i = 1, #rhs do
res[i + l] = rhs[i]
end
return setmetatable(res, getmetatable(lhs) or getmetatable(rhs))
else
return tostring(lhs) .. tostring(rhs)
end
end

function Array.__unm(arr)
return Array.map(arr, function(x) return -x end)
end

---@param lhs number|number[]|Array
---@param rhs number|number[]|Array
---@param funName string
---@param opName string
---@param fun fun(lhs: number, rhs: number): number
---@return Array
local function mathTemplate(lhs, rhs, funName, opName, fun)
checkTypeMulti('Module:Array.' .. funName, 1, lhs, {'number', 'table'})
checkTypeMulti('Module:Array.' .. funName, 2, rhs, {'number', 'table'})
local res = {}

if type(lhs) == 'number' then
for i = 1, #rhs do
res[i] = fun(lhs, rhs[i])
end
elseif type(rhs) == 'number' then
for i = 1, #lhs do
res[i] = fun(lhs[i], rhs)
end
else
assert(#lhs == #rhs, string.format('Elementwise %s failed because arrays have different sizes (left: %d, right: %d)', opName, #lhs, #rhs))
for i = 1, #lhs do
res[i] = fun(lhs[i], rhs[i])
end
end

return setmetatable(res, getmetatable(lhs) or getmetatable(rhs))
end

function Array.__add(lhs, rhs)
return mathTemplate(lhs, rhs, '__add', 'addition', function(x, y) return x + y end)
end

function Array.__sub(lhs, rhs)
return mathTemplate(lhs, rhs, '__sub', 'substraction', function(x, y) return x - y end)
end

function Array.__mul(lhs, rhs)
return mathTemplate(lhs, rhs, '__mul', 'multiplication', function(x, y) return x * y end)
end

function Array.__div(lhs, rhs)
return mathTemplate(lhs, rhs, '__div', 'division', function(x, y) return x / y end)
end

function Array.__pow(lhs, rhs)
return mathTemplate(lhs, rhs, '__pow', 'exponentiation', function(x, y) return x ^ y end)
end

function Array.__eq(lhs, rhs)
if #lhs ~= #rhs then
return false
end
for i = 1, #lhs do
if lhs[i] ~= rhs[i] then
return false
end
end
return true
end

---Behaviour depends on the value of `fn`:
---* `nil` - Checks that the array doesn't contain any **false** elements.
---* `fun(elem: any, i?: integer): boolean` - Returns **true** if `fn` returns **true** for every element.
---* `number` | `table` | `boolean` - Checks that all elements in `arr` are equal to this value.
---@param arr any[]
---@param fn? any
---@return boolean
function Array.all(arr, fn)
checkType('Module:Array.all', 1, arr, 'table')
if fn == nil then fn = function(item) return item end end
if type(fn) ~= 'function' then
local val = fn
fn = function(item) return item == val end
end
local i = 1
while arr[i] ~= nil do
---@diagnostic disable-next-line: redundant-parameter
if not fn(arr[i], i) then
return false
end
i = i + 1
end
return true
end

---Behaviour depends on the value of `fn`:
---* `nil` - Checks that the array contains at least one non **false** element.
---* `fun(elem: any, i?: integer): boolean` - Returns **true** if `fn` returns **true** for at least one element.
---* `number` | `table` | `boolean` - Checks that `arr` contains this value.
---@param arr any[]
---@param fn? any
---@return boolean
function Array.any(arr, fn)
checkType('Module:Array.any', 1, arr, 'table')
if fn == nil then fn = function(item) return item end end
if type(fn) ~= 'function' then
local val = fn
fn = function(item) return item == val end
end
local i = 1
while arr[i] ~= nil do
---@diagnostic disable-next-line: redundant-parameter
if fn(arr[i], i) then
return true
end
i = i + 1
end
return false
end

---Recursively removes all metatables.
---@param arr any[]
---@return any[]
function Array.clean(arr)
checkType('Module:Array.clean', 1, arr, 'table')
for i = 1, #arr do
if type(arr[i]) == 'table' then
Array.clean(arr[i])
end
end
setmetatable(arr, nil)
return arr
end

---Make a copy of the input table. Preserves metatables.
---@generic T: any[]
---@param arr T
---@param deep? boolean # Recursively clone subtables if **true**.
---@return T
function Array.clone(arr, deep)
checkType('Module:Array.clone', 1, arr, 'table')
checkType('Module:Array.clone', 2, deep, 'boolean', true)
local res = {}
for i = 1, #arr do
if deep == true and type(arr[i]) == 'table' then
res[i] = Array.clone(arr[i], true)
else
res[i] = arr[i]
end
end
return setmetatable(res, getmetatable(arr))
end

---Check if `arr` contains `val`.
---@param arr any[]
---@param val any
---@return boolean
function Array.contains(arr, val)
checkType('Module:Array.contains', 1, arr, 'table')
for i = 1, #arr do
if arr[i] == val then
return true
end
end
return false
end

---Check if `arr` contains any of the values in the table `t`.
---@param arr any[]
---@param t any[]
---@return boolean
function Array.containsAny(arr, t)
checkType('Module:Array.containsAny', 1, arr, 'table')
checkType('Module:Array.containsAny', 2, t, 'table')
local lookupTbl = {}
for i = 1, #t do
lookupTbl[t[i]] = true
end
for i = 1, #arr do
if lookupTbl[arr[i]] then
return true
end
end
return false
end

---Check if `arr` contains all values in the table `t`.
---@param arr any[]
---@param t any[]
---@return boolean
function Array.containsAll(arr, t)
checkType('Module:Array.containsAll', 1, arr, 'table')
checkType('Module:Array.containsAll', 2, t, 'table')
local lookupTbl = {}
local l = #t
local trueCount = 0
for i = 1, l do
lookupTbl[t[i]] = false
end
for i = 1, #arr do
if lookupTbl[arr[i]] == false then
lookupTbl[arr[i]] = true
trueCount = trueCount + 1
end
if trueCount == l then
return true
end
end
return false
end

---Convolute two number arrays.
---@generic T: number[]
---@param x T
---@param y T
---@return T
function Array.convolve(x, y)
checkType('Module:Array.convolve', 1, x, 'table')
checkType('Module:Array.convolve', 2, y, 'table')
local z = {}
local xLen, yLen = #x, #y
for j = 1, (xLen + yLen - 1) do
local sum = 0
for k = math.max(1, j - yLen + 1), math.min(xLen, j) do
sum = sum + x[k] * y[j-k+1]
end
z[j] = sum
end
return setmetatable(z, getmetatable(x) or getmetatable(y))
end

---Remove **nil** values from `arr` while preserving order.
---@generic T: any[]
---@param arr T
---@return T
function Array.condenseSparse(arr)
checkType('Module:Array.condenseSparse', 1, arr, 'table')
local keys = {}
local res = {}
local l = 0
for k in pairs(arr) do
l = l + 1
keys[l] = k
end
table.sort(keys)
for i = 1, l do
res[i] = arr[keys[i]]
end
return setmetatable(res, getmetatable(arr))
end

---Behaviour depends on value of `val`:
---* `nil` - Counts the number of non **false** elements.
---* `fun(elem: any): boolean` - Count the number of times the function returned **true**.
---* `boolean` | `number` | `table` - Counts the number of times this value occurs in `arr`.
---@param arr any[]
---@param val? any
---@return integer
function Array.count(arr, val)
checkType('Module:Array.count', 1, arr, 'table')
if val == nil then val = function(item) return item end end
if type(val) ~= 'function' then
local _val = val
val = function(item) return item == _val end
end
local count = 0
for i = 1, #arr do
if val(arr[i]) then
count = count + 1
end
end
return count
end

---Differentiate the array
---@generic T: number[]
---@param arr T
---@param order number? # Oder of the differentiation. Default is 1.
---@return T # Length is `#arr - order`
function Array.diff(arr, order)
checkType('Module:Array.diff', 1, arr, 'table')
checkType('Module:Array.diff', 2, order, 'number', true)
local res = {}
for i = 1, #arr - 1 do
res[i] = arr[i+1] - arr[i]
end
if order and order > 1 then
return Array.diff(res, order - 1)
end
return setmetatable(res, getmetatable(arr))
end

---Loops over `arr` and passes each element as the first argument to `fn`. This function returns nothing.
---@param arr any[]
---@param fn fun(elem: any, i?: integer)
function Array.each(arr, fn)
checkType('Module:Array.each', 1, arr, 'table')
checkType('Module:Array.each', 2, fn, 'function')
local i = 1
while arr[i] ~= nil do
fn(arr[i], i)
i = i + 1
end
end

---Makes a copy of `arr` with only elements for which `fn` returned **true**.
---@generic T: any[]
---@param arr T
---@param fn fun(elem: any, i?: integer): boolean
---@return T
function Array.filter(arr, fn)
checkType('Module:Array.filter', 1, arr, 'table')
checkType('Module:Array.filter', 2, fn, 'function')
local r = {}
local len = 0
local i = 1
while arr[i] ~= nil do
if fn(arr[i], i) then
len = len + 1
r[len] = arr[i]
end
i = i + 1
end
return setmetatable(r, getmetatable(arr))
end

---Find the first elements for which `fn` returns **true**.
---@param arr any[]
---@param fn any # A value to look for or a function of the form `fun(elem: any, i?: integer): boolean`.
---@param default? any # Value to return if no element passes the test.
---@return any? elem # The first element that passed the test.
---@return integer? i # The index of the item that passed the test.
function Array.find(arr, fn, default)
checkType('Module:Array.find', 1, arr, 'table')
checkTypeMulti('Module:Array.find_index', 2, fn, {'function', 'table', 'number', 'boolean'})
if type(fn) ~= 'function' then
local _val = fn
fn = function(item) return item == _val end
end
local i = 1
while arr[i] ~= nil do
---@diagnostic disable-next-line: redundant-parameter
if fn(arr[i], i) then
return arr[i], i
end
i = i + 1
end
return default, nil
end

---Find the index of `val`.
---@param arr any[]
---@param val any # A value to look for or a function of the form `fun(elem: any, i?: integer): boolean`.
---@param default? any # Value to return if no element passes the test.
---@return integer?
function Array.find_index(arr, val, default)
checkType('Module:Array.find_index', 1, arr, 'table')
checkTypeMulti('Module:Array.find_index', 2, val, {'function', 'table', 'number', 'boolean'})
if type(val) ~= 'function' then
local _val = val
val = function(item) return item == _val end
end
local i = 1
while arr[i] ~= nil do
---@diagnostic disable-next-line: redundant-parameter
if val(arr[i], i) then
return i
end
i = i + 1
end
return default
end

---Extracts a subset of `arr`.
---@generic T: any[]
---@param arr T
---@param indexes integer|integer[] # Indexes of the elements.
---@return T
function Array.get(arr, indexes)
checkType('Module:Array.set', 1, arr, 'table')
checkTypeMulti('Module:Array.set', 2, indexes, {'table', 'number'})
if type(indexes) == 'number' then
indexes = {indexes}
end
local res = {}
for i = 1, #indexes do
res[i] = arr[indexes[i]]
end
return setmetatable(res, getmetatable(arr))
end

---Integrates the array. Effectively does $\left\{\sum^{n}_{start}{arr[n]} \,\Bigg|\, n \in [start, stop]\right\}$.
---@generic T: number[]
---@param arr T # number[]
---@param start? integer # Index where to start the summation. Defaults to 1.
---@param stop? integer # Index where to stop the summation. Defaults to #arr.
---@return T
function Array.int(arr, start, stop)
checkType('Module:Array.int', 1, arr, 'table')
checkType('Module:Array.int', 2, start, 'number', true)
checkType('Module:Array.int', 3, stop, 'number', true)
local res = {}
start = start or 1
stop = stop or #arr
res[1] = arr[start]
for i = 1, stop - start do
res[i+1] = res[i] + arr[start + i]
end
return setmetatable(res, getmetatable(arr))
end

---Returns an array with elements that are present in both tables.
---@generic T: any[]
---@param arr1 T
---@param arr2 T
---@return T
function Array.intersect(arr1, arr2)
checkType('Module:Array.intersect', 1, arr1, 'table')
checkType('Module:Array.intersect', 2, arr2, 'table')
local arr2Elements = {}
local res = {}
local len = 0
Array.each(arr2, function(item) arr2Elements[item] = true end)
Array.each(arr1, function(item)
if arr2Elements[item] then
len = len + 1
res[len] = item
end
end)
return setmetatable(res, getmetatable(arr1) or getmetatable(arr2))
end

---Checks if the two inputs have at least one element in common.
---@param arr1 any[]
---@param arr2 any[]
---@return boolean
function Array.intersects(arr1, arr2)
checkType('Module:Array.intersects', 1, arr1, 'table')
checkType('Module:Array.intersects', 2, arr2, 'table')
local small = {}
local large
if #arr1 <= #arr2 then
Array.each(arr1, function(item) small[item] = true end)
large = arr2
else
Array.each(arr2, function(item) small[item] = true end)
large = arr1
end
return Array.any(large, function(item) return small[item] end)
end

---Inserts values into `arr`.
---@generic T: any[]
---@param arr T
---@param val any # If `val` is an array and `unpackVal` is **true** then the individual elements of `val` are inserted.
---@param index? integer # Location to start the insertion. Default is at the end of `arr`.
---@param unpackVal? boolean # Default is **false**.
---@return T
---@overload fun(arr: T, val: any, unpackVal: boolean): T
function Array.insert(arr, val, index, unpackVal)
checkType('Module:Array.insert', 1, arr, 'table')
checkTypeMulti('Module:Array.insert', 3, index, {'number', 'boolean', 'nil'})
checkType('Module:Array.insert', 4, unpackVal, 'boolean', true)
if type(index) == 'boolean' then
unpackVal, index = index, nil
end
local len = #arr
index = index or (len + 1)
local mt = getmetatable(arr)
setmetatable(arr, nil)

if type(val) == 'table' and unpackVal then
local len2 = #val
for i = 0, len - index do
arr[len + len2 - i] = arr[len - i]
end
for i = 0, len2 - 1 do
arr[index + i] = val[i + 1]
end
else
table.insert(arr, index, val)
end

return setmetatable(arr, mt)
end

---Returns the last element of `arr`.
---@param arr any[]
---@param offset? integer
---@return any
function Array.last(arr, offset)
checkType('Module:Array.last', 1, arr, 'table')
checkType('Module:Array.last', 2, offset, 'number', true)
return arr[#arr + offset]
end

---Returns a new table were each element of `arr` is modified by `fn`.
---@generic T: any[]
---@param arr T
---@param fn fun(elem: any, i?: integer): any # First argument is the current element, the second argument is the index of the current element.
---@return T
function Array.map(arr, fn)
checkType('Module:Array.map', 1, arr, 'table')
checkType('Module:Array.map', 2, fn, 'function')
local len = 0
local r = {}
local i = 1
while arr[i] ~= nil do
local tmp = fn(arr[i], i)
if tmp ~= nil then
len = len + 1
r[len] = tmp
end
i = i + 1
end
return setmetatable(r, getmetatable(arr))
end

---Find the element for which `fn` returned the largest value.
---@param arr any[]
---@param fn fun(elem: any): any # The returned value needs to be comparable using the `<` operator.
---@return any elem # The element with the largest `fn` value.
---@return integer i # The index of this element.
function Array.max_by(arr, fn)
checkType('Module:Array.max_by', 1, arr, 'table')
checkType('Module:Array.max_by', 2, fn, 'function')
return unpack(Array.reduce(arr, function(new, old, i)
local y = fn(new)
return y > old[2] and {new, y, i} or old
end, {nil, -math.huge}))
end

---Find the largest value in the array.
---@param arr any[] # The values need to be comparable using the `<` operator.
---@return any elem
---@return integer i # The index of the largest value.
function Array.max(arr)
checkType('Module:Array.max', 1, arr, 'table')
local val, _, i = Array.max_by(arr, function(x) return x end)
return val, i
end

---Find the smallest value in the array.
---@param arr any[] # The values need to be comparable using the `<` operator.
---@return any elem
---@return integer i # The index of the smallest value.
function Array.min(arr)
checkType('Module:Array.min', 1, arr, 'table')
local val, _, i = Array.max_by(arr, function(x) return -x end)
return val, i
end

---Turn the input table into an Array. This makes it possible to use the colon `:` operator to access the Array methods.
---
---It also enables the use of math operators with the array.
---```
---local x = arr.new{ 1, 2, 3 }
---local y = arr{ 4, 5, 6 } -- Alternative notation
---
---print( -x ) --> { -1, -2, -3 }
---print( x + 2 ) --> { 3, 4, 5 }
---print( x - 2 ) --> { -1, 0, 1 }
---print( x * 2 ) --> { 2, 4, 6 }
---print( x / 2 ) --> { 0.5, 1, 1.5 }
---print( x ^ 2 ) --> { 1, 4, 9 }
---
---print( x + y ) --> { 5, 7, 9 }
---print( x .. y ) --> { 1, 2, 3, 4, 5, 6 }
---print( (x .. y):reject{3, 4, 5} ) --> { 1, 2, 6 }
---print( x:sum() ) --> 6
---
---print( x:update( {1, 3}, y:get{2, 3} * 2 ) ) --> { 10, 2, 12 }
---```
---@param arr? any[]
---@return Array
function Array.new(arr)
local obj = arr or {}
for _, v in pairs(obj) do
if type(v) == 'table' then
Array.new(v)
end
end

if getmetatable(obj) == nil then
setmetatable(obj, Array)
end

return obj
end

---Creates an object that returns a value that is `step` higher than the previous value each time it gets called.
---
---The stored value can be read without incrementing by reading the `val` field.
---
---A new stored value can be set through the `val` field.
---
---A new step size can be set through the `step` field.
---```
---local inc = arr.newIncrementor(10, 5)
---print( inc() ) --> 10
---print( inc() ) --> 15
---print( inc.val ) --> 15
---inc.val = 100
---inc.step = 20
---print( inc.val ) --> 100
---print( inc() ) --> 120
---```
---@param start? number # Default is 1.
---@param step? number # Default is 1.
---@return Incrementor
function Array.newIncrementor(start, step)
checkType('Module:Array.newIncrementor', 1, start, 'number', true)
checkType('Module:Array.newIncrementor', 2, step, 'number', true)
step = step or 1
local n = (start or 1) - step
---@class Incrementor
local obj = {}
return setmetatable(obj, {
__call = function() n = n + step return n end,
__tostring = function() return n end,
__index = function() return n end,
__newindex = function(self, k, v)
if k == 'step' and type(v) == 'number' then
step = v
elseif type(v) == 'number' then
n = v
end
end,
__concat = function(x, y) return tostring(x) .. tostring(y) end
})
end

---Returns a range of numbers.
---@param start number # Start value inclusive.
---@param stop number # Stop value inclusive for integers, exclusive for floats.
---@param step? number # Default is 1.
---@return Array
---@overload fun(stop: number): Array
function Array.range(start, stop, step)
checkType('Module:Array.range', 1, start, 'number')
checkType('Module:Array.range', 2, stop, 'number', true)
checkType('Module:Array.range', 3, step, 'number', true)
local arr = {}
local len = 0
if not stop then
stop = start
start = 1
end
for i = start, stop, step or 1 do
len = len + 1
arr[len] = i
end
return setmetatable(arr, Array)
end

---Condenses the array into a single value.
---
---For each element `fn` is called with the current element, the current accumulator, and the current element index. The returned value of `fn` becomes the accumulator for the next element.
---
---If no `accumulator` value is given at the start then the first element off `arr` becomes the accumulator and the iteration starts from the second element.
---```
---local t = { 1, 2, 3, 4 }
---local sum = arr.reduce( t, function(elem, acc) return acc + elem end ) -- sum == 10
---```
---@param arr any[]
---@param fn fun(elem: any, acc: any, i?: integer): any # The result of this function becomes the `acc` for the next element.
---@param accumulator? any
---@return any # This is the last accumulator value.
function Array.reduce(arr, fn, accumulator)
checkType('Module:Array.reduce', 1, arr, 'table')
checkType('Module:Array.reduce', 2, fn, 'function')
local acc = accumulator
local i = 1
if acc == nil then
acc = arr[1]
i = 2
end
while arr[i] ~= nil do
acc = fn(arr[i], acc, i)
i = i + 1
end
return acc
end

---Make a copy off `arr` with certain values removed.
---
---Behaviour for different values of `val`:
---* `boolean` | `number` - Remove values equal to this.
---* `table` - Remove all values in this table.
---* `fun(elem: any, i?: integer): boolean` - Remove elements for which the functions returns **true**.
---@generic T: any[]
---@param arr T
---@param val table|function|number|boolean
---@return T
function Array.reject(arr, val)
checkType('Module:Array.reject', 1, arr, 'table')
checkTypeMulti('Module:Array.reject', 2, val, {'function', 'table', 'number', 'boolean'})
if type(val) ~= 'function' and type(val) ~= 'table' then
val = {val}
end
local r = {}
local len = 0
if type(val) == 'function' then
local i = 1
while arr[i] ~= nil do
if not val(arr[i], i) then
len = len + 1
r[len] = arr[i]
end
i = i + 1
end
else
local rejectMap = {}
Array.each(val --[[@as any[] ]], function(item) rejectMap[item] = true end)
local i = 1
while arr[i] ~= nil do
if not rejectMap[arr[i]] then
len = len + 1
r[len] = arr[i]
end
i = i + 1
end
end
return setmetatable(r, getmetatable(arr))
end

---Returns an Array with `val` repeated `n` times.
---@param val any
---@param n integer
---@return Array
function Array.rep(val, n)
checkType('Module:Array.rep', 2, n, 'number')
local r = {}
for i = 1, n do
r[i] = val
end
return setmetatable(r, Array)
end

---Condenses the array into a single value while saving every accumulator value.
---
---For each element `fn` is called with the current element, the current accumulator, and the current element index. The returned value of `fn` becomes the accumulator for the next element.
---
---If no `accumulator` value is given at the start then the first element off `arr` becomes the accumulator and the iteration starts from the second element.
---```
---local t = { 1, 2, 3, 4 }
---local x = arr.scan( t, function(elem, acc) return acc + elem end ) -- x = { 1, 3, 6, 10 }
---```
---@generic T: any[]
---@param arr T
---@param fn fun(elem: any, acc: any, i?: integer): any # Returned value becomes the accumulator for the next element.
---@param accumulator? any
---@return T
function Array.scan(arr, fn, accumulator)
checkType('Module:Array.scan', 1, arr, 'table')
checkType('Module:Array.scan', 2, fn, 'function')
local acc = accumulator
local r = {}
local i = 1
while arr[i] ~= nil do
if i == 1 and not accumulator then
acc = arr[i]
else
acc = fn(arr[i], acc, i)
end
r[i] = acc
i = i + 1
end
return setmetatable(r, getmetatable(arr))
end

---Update a range of index with a range of values.
---
---If if only one value is given but multiple indexes than that value is set for all those indexes.
---
---If `values` is a table then it must of the same length as `indexes`.
---@generic T: any[]
---@param arr T
---@param indexes integer|integer[]
---@param values any|any[]
---@return T
function Array.set(arr, indexes, values)
checkType('Module:Array.set', 1, arr, 'table')
checkTypeMulti('Module:Array.set', 2, indexes, {'table', 'number'})
local mt = getmetatable(arr)
setmetatable(arr, nil)
if type(indexes) == 'number' then
indexes = {indexes}
end
if type(values) == 'table' then
assert(#indexes == #values, string.format("Module:Array.set: 'indexes' and 'values' arrays are not equal length (#indexes = %d, #values = %d)", #indexes, #values))
for i = 1, #indexes do
arr[indexes[i]] = values[i]
end
else
for i = 1, #indexes do
arr[indexes[i]] = values
end
end
return setmetatable(arr, mt)
end

---Extract a subtable from `arr`.
---@generic T: any[]
---@param arr T
---@param start integer # Start index. Use negative values to count form the end of the array.
---@param stop integer # Stop index. Use negative values to count form the end of the array.
---@return T
---@overload fun(arr: T, stop: integer): T
function Array.slice(arr, start, stop)
checkType('Module:Array.slice', 1, arr, 'table')
checkType('Module:Array.slice', 2, start, 'number', true)
checkType('Module:Array.slice', 3, stop, 'number', true)
start = start or #arr
if start < 0 then
start = #arr + start
end
if stop == nil then
stop = start
start = 1
end
if stop < 0 then
stop = #arr + stop
end
local r = {}
local len = 0
for i = start, stop do
len = len + 1
r[len] = arr[i]
end
return setmetatable(r, getmetatable(arr))
end

---Split `arr` into two arrays.
---@generic T: any[]
---@param arr T
---@param index integer # Index to split on.
---@return T x # [1, index]
---@return T y # [index + 1, #arr]
function Array.split(arr, index)
checkType('Module:Array.split', 1, arr, 'table')
checkType('Module:Array.split', 2, index, 'number')
local x = {}
local y = {}
for i = 1, #arr do
table.insert(i <= index and x or y, arr[i])
end
return setmetatable(x, getmetatable(arr)), setmetatable(y, getmetatable(arr))
end

---Returns the sum of all elements of `arr`.
---@param arr number[]
---@return number
function Array.sum(arr)
checkType('Module:Array.sum', 1, arr, 'table')
local res = 0
for i = 1, #arr do
res = res + arr[i]
end
return res
end

---Extract a subtable from `arr`.
---@generic T: any[]
---@param arr T
---@param count integer # Length of the subtable.
---@param start? integer # Start index. Default is 1.
---@return T
function Array.take(arr, count, start)
checkType('Module:Array.take', 1, arr, 'table')
checkType('Module:Array.take', 2, count, 'number')
checkType('Module:Array.take', 3, start, 'number', true)
local x = {}
start = start or 1
for i = start, math.min(#arr, count + start - 1) do
table.insert(x, arr[i])
end
return setmetatable(x, getmetatable(arr))
end

---Extract a subtable from `arr`.
---```
---local t = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 }
---local x = arr.take_every( t, 2 ) --> x = { 1, 3, 5, 7, 9 }
---local x = arr.take_every( t, 2, 3 ) --> x = { 1, 3, 5 }
---local x = arr.take_every( t, 2, 3, 2 ) --> x = { 2, 4, 6 }
--- ```
---@generic T: any[]
---@param arr T
---@param n integer # Step size.
---@param start? integer # Start index.
---@param count? integer # Max amount of elements to get.
---@return T
function Array.take_every(arr, n, start, count)
checkType('Module:Array.take_every', 1, arr, 'table')
checkType('Module:Array.take_every', 2, n, 'number')
checkType('Module:Array.take_every', 3, start, 'number', true)
checkType('Module:Array.take_every', 4, count, 'number', true)
count = count or #arr
local r = {}
local len = 0
local i = start or 1
while arr[i] ~= nil and len < count do
len = len + 1
r[len] = arr[i]
i = i + n
end
return setmetatable(r, getmetatable(arr))
end

---Return a new table with all duplicates removed.
---@generic T: any[]
---@param arr T
---@param fn? fun(elem: any): any # Function to generate an id for each element. The result will then contain elements that generated unique ids.
---@return T
function Array.unique(arr, fn)
checkType('Module:Array.unique', 1, arr, 'table')
checkType('Module:Array.unique', 2, fn, 'function', true)
fn = fn or function(item) return item end
local r = {}
local len = 0
local hash = {}
local i = 1
while arr[i] ~= nil do
local id = fn(arr[i])
if not hash[id] then
len = len + 1
r[len] = arr[i]
hash[id] = true
end
i = i + 1
end
return setmetatable(r, getmetatable(arr))
end

---Combine elements with the same index from multiple arrays.
---```
---local x = {1, 2, 3}
---local y = {4, 5, 6, 7}
---local z = arr.zip( x, y ) --> z = { { 1, 4 }, { 2, 5 }, { 3, 6 }, { 7 } }
---```
---@param ... any[]
---@return Array
function Array.zip(...)
local arrs = { ... }
checkType('Module:Array.zip', 1, arrs[1], 'table')
local r = {}
local _, longest = Array.max_by(arrs, function(arr) return #arr end)
for i = 1, longest do
local q = {}
for j = 1, #arrs do
table.insert(q, arrs[j][i])
end
table.insert(r, setmetatable(q, Array))
end
return setmetatable(r, Array)
end

-- Range indexing has a performance impact so this is placed in a separate subclass
Array.RI_mt = {}
for k, v in pairs(Array) do
Array.RI_mt[k] = v
end

function Array.RI_mt.__index(t, k)
if type(k) == 'table' then
local res = {}
for i = 1, #k do
res[i] = t[k[i]]
end
return setmetatable(res, Array)
else
return Array[k]
end
end

function Array.RI_mt.__newindex(t, k, v)
if type(k) == 'table' then
if type(v) == 'table' then
for i = 1, #k do
t[k[i]] = v[i]
end
else
for i = 1, #k do
t[k[i]] = v
end
end
else
rawset(t, k, v)
end
end

---Enable range indexing on the input array.
---
---This has a performance impact on reads and writes to the table.
---```
---local t = arr{10, 11, 12, 13, 14, 15}:ri()
---print( t[{2, 3}] ) --> { 11, 12 }
---```
---@param arr any[]
---@param recursive? boolean # Default is false.
---@return Array
function Array.ri(arr, recursive)
checkType('Module:Array.ri', 1, arr, 'table')
checkType('Module:Array.ri', 2, recursive, 'boolean', true)
arr = arr or {}
if recursive then
for _, v in pairs(arr) do
if type(v) == 'table' then
Array.ri(v, true)
end
end
end

if getmetatable(arr) == nil or getmetatable(arr) == Array then
setmetatable(arr, Array.RI_mt)
end

return arr
end

---Globally enable range indexing on all Array objects by default.
---@param set boolean
function Array.allwaysAllowRangeIndexing(set)
checkType('Module:Array.allwaysAllowRangeIndexing', 1, set, 'boolean')
if set then
Array.__index = Array.RI_mt.__index
Array.__newindex = Array.RI_mt.__newindex
else
Array.__index = Array
Array.__newindex = nil
end
end

return Array

Module:Array - Revision history